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State Responsibility for International Terrorism$

Kimberley N. Trapp

Print publication date: 2011

Print ISBN-13: 9780199592999

Published to Oxford Scholarship Online: September 2011

DOI: 10.1093/acprof:oso/9780199592999.001.0001

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The prohibition of state terrorism and questions of attribution

The prohibition of state terrorism and questions of attribution

Chapter:
(p.24) 2 The prohibition of state terrorism and questions of attribution
Source:
State Responsibility for International Terrorism
Author(s):

Kimberley N. Trapp

Publisher:
Oxford University Press
DOI:10.1093/acprof:oso/9780199592999.003.0002

Abstract and Keywords

Chapter 2 explores the obligations to refrain from engaging in or supporting acts of international terrorism as specific instantiations of the general international law prohibitions of aggression and the use of force, and the principle of non-intervention. It further examines the secondary rules of attribution as they apply in the terrorism context (informing the analysis of which prohibition is breached), and critically engages with arguments that the rules of attribution are inadequate to meet the threat of terrorism. In particular, Chapter 2 argues that the ‘effective control’ standard for attribution adopted by the ICJ in Nicaragua was driven by the facts of the case and is ill-suited to determine State involvement in international terrorism. Chapter 2 advocates instead a context-sensitive application of Article 8 of the ILC Articles on State Responsibility and further argues that the ICJ’s jurisprudence and relevant State practice do not support complicity as an emerging basis of attribution for acts of terrorism.

Keywords:   State terrorism, aggression, use of force, non-intervention, attribution, Nicaragua Case, Tadic, effective control, overall control, complicity

Former UN Secretary-General Kofi Annan has argued that ‘[i]t is time to set aside debates on so-called “State terrorism”. The use of force by States is already thoroughly regulated under international law’.1 This statement of principle, denying the existence of a lex specialis prohibiting acts of terrorism carried out by states, is one that is confirmed by the examination of general international law set out below. Nevertheless, the term ‘state terrorism’ is a useful one—principally because the term ‘terrorism’ describes a sphere of violent conduct that states have singled out as requiring particular regulation through the regime of TSCs and relevant General Assembly and Security Council resolutions,2 and the term ‘state terrorism’ merely highlights the possibility of state sponsorship and support for acts that fall within that regime.

State sponsorship of terrorism is the term used in this book to denote terrorist conduct that is carried out by or on behalf of a state,3 i.e. terrorist conduct which is attributable to the state. State support for terrorism refers to a state’s assistance in the commission of terrorist acts in cases where the act is not attributable to the state. State support can take many forms, including training, financial support, provision of arms and/or technology, assistance with diplomatic assets (provision of passports and other forms of cover), provision of transportation or intelligence and permitting use of territory as a base of operations.4 The distinction between state sponsorship and state support for terrorism (examined in Section 2.1 below) plays a role in determining which primary rule is engaged by a state’s involvement in terrorism, in particular whether the state can be held responsible for an act of aggression, a prohibited use of force, or an intervention in the domestic affairs of a foreign state. The rules of attribution as they apply in the terrorism context are examined in Section 2.2.

(p.25) 2.1 The prohibition of state terrorism

The prohibition of state sponsorship of and support for acts of terrorism was the subject of much debate during consultations on the UN Definition of Aggression and the UN Declaration on Friendly Relations.5 The UN Declaration on Friendly Relations in particular considers state terrorism through the prism of the UN Charter,6 and thereby confirms the argument that terrorism, particularly with state involvement, ‘is not a discrete topic of international law with its own substantive legal norms’, but a contemporary phenomenon to which existing international law applies.7 The precise scope of states’ obligations to refrain from engaging in or supporting acts of international terrorism is therefore best examined through its Charter-related development as regards the prohibition of aggression, the prohibition of the use of force, and the principle of non-intervention (considered in turn below). While the prohibition of state terrorism features expressly in the UN Declaration on Friendly Relations, both in reference to prohibited uses of force and impermissible interventions, it was not ultimately included in the UN Definition of Aggression. Nevertheless, state sponsorship of an act of terrorism will, in certain circumstances, amount to a prohibited act of aggression as defined in the UN Definition of Aggression.

It bears noting that the UN instruments discussed below do not define terrorism, although they do treat terrorism as a type of state violence meriting particular attention. States have, however, defined terrorism in other contexts, particularly through the negotiation of the TSCs and more recently in General Assembly and Security Council resolutions.8 Even though these instruments are aimed principally at acts of terrorism carried out by individuals, they are indicative of the type of violence that states consider to be ‘terrorist’—and therefore fall within the prohibition of state terrorism as an instantiation of general prohibitions on state violence under international law.

2.1.1 The prohibition of aggression

The Special Committee on the Question of Defining Aggression spent a great deal of time debating whether the definition of aggression should include ‘indirect armed aggression’, in particular, acts of state-sponsored or supported terrorism.9 (p.26) It was generally agreed that state terrorism would amount to a breach of the peace or an illegal intervention in the domestic affairs of another state.10 Western states, however, insisted that the ‘organization, instigation of, assistance or participation in terrorist acts in other states’ should figure in the definition of aggression.11 The Soviet Union preferred to distinguish between aggression and indirect aggression,12 while the Non-Aligned Movement raised objections to the concept of indirect aggression altogether. The NAM was pre-occupied with the relationship between the definition of aggression and the definition of an armed attack under Article 51 of the UN Charter.13 They were particularly concerned that a failure to limit the definition of aggression to direct (attributable) state action raised the possibility of powerful states disingenuously accusing weaker states of acquiescing in armed bands operating from their territory to justify an aggressive use of force (under the guise of self-defence) against that weaker state.14 On the other hand, Western states supporting the inclusion of indirect aggression in the definition argued that failing to do so would threaten international peace as it would encourage states to engage in wars by proxy emboldened by the belief that they could not be charged with aggression.15 As a result of the impasse, the UN Definition of Aggression does not address terrorism as such. Several delegates expressed discontent with the final text because it omitted acts that they thought should have been covered.16

The definition of aggression finally adopted by the General Assembly is clearly limited to acts carried out by a state. Article 1 of the UN Definition of Aggression defines aggression as ‘the use of armed force by a State against the sovereignty, territorial integrity or political independence of another State […]’.17 The use of armed force, however, need not be carried out by a state’s military forces: ‘sending by or on behalf of a State of armed bands, groups, irregulars or mercenaries, which (p.27) carry out acts [amounting to aggression], or its substantial involvement therein’ also amounts to aggression.18 Article 3 of the UN Definition of Aggression is intended to provide a non-exhaustive list of acts that amount to aggression within the meaning of Article 1. As such, the ‘sending by or on behalf of a State of armed bands […], or […] substantial involvement therein’ must be interpreted as a lex specialis threshold for attributing the aggression carried out by the armed bands to the state sending them,19 thereby maintaining the Article 1 requirement that an act of aggression be a ‘use of armed force by a State’.20 Some commentators argue that ‘sending’ does not invoke a standard of attribution, and question whether it might include permitting or tolerating the activities of armed bands.21 Such an argument, however, is inconsistent with the terms of Article 1 of the UN Definition of Aggression. Indeed, proposals to minimize the level of state involvement required for an act of aggression, including ‘assistance to’, ‘knowing acquiescence in’, or ‘collaboration in’22 (all of which would amount to active or passive support for, rather than sponsorship of, armed bands) were rejected in favour of the ‘sending by or on behalf of’ standard. As such, no form of indirect aggression made its way into the UN Definition of Aggression, which applies only to state sponsorship of terrorism, and not to state support for terrorism involving some lesser form of assistance to non-state terrorist actors.23

(p.28) An act of terrorism amounting to aggression carried out by non-state actors that is attributable to a state (in virtue of that state having sent the armed bands) will constitute aggression. As a result, Article 3(g) of the UN Definition of Aggression elaborates part of the customary international law content of the obligation to refrain from engaging in acts of terrorism.24 The circumstances under which a state’s sponsorship of terrorism will amount to an act of aggression as defined in the UN Definition of Aggression are rare, but not entirely unlikely. For instance, consider the nineteen men who hijacked American Airlines (‘AA’) Flight 11, United Airlines (‘UA’) Flight 175, AA Flight 77, and UA Flight 93 on 11 September 2001 and flew the aircraft into the World Trade Center north and south towers, the Pentagon and an empty field in Pennsylvania respectively.25 That the 9/11 attacks amounted to acts of terrorism as defined in Chapter 1 is indisputable: they were acts intended to cause death or serious bodily injury to civilians, and their purpose was certainly to provoke a state of terror and to compel a government to do or abstain from doing any act.26 It is equally clear that the use of force by the hijackers (using commercial aircraft as targeted missiles against civilian and military targets) was of such gravity that it would have amounted to an act of aggression had it been carried out by a state’s military.27 Had a state sent the suicide hijackers, the 9/11 terrorist attacks would therefore have met the definition of aggression, in that the ‘sending by or on behalf of a State’ test for aggression would be met.28

2.1.2 The prohibition of the use of force

The UN Declaration on Friendly Relations codified and progressively developed29 the prohibition of the use of force set out in Article 2(4) of the UN Charter,30 but has since been held to reflect customary international law.31 It characterizes the prohibition of state terrorism as an instantiation of the general prohibition of the use of force, and affirms that it is the duty of every state to ‘refrain from organizing, (p.29) instigating, assisting or participating in acts of civil strife or terrorist acts in another State or acquiescing in organized activities within its territory directed toward the commission of such acts, when the acts referred to in the present paragraph involve a threat or use of force’.32

State sponsorship of terrorism amounts to an illegal use of force pursuant to the UN Declaration on Friendly Relations in that states are prohibited from participating in terrorist acts in another state. The direct participation of state organs in a terrorist attack would result in that attack being attributable to the state. France’s use of a state organ (secret service agents) to destroy the ‘Rainbow Warrior’ Greenpeace ship in Auckland Harbour33 amounted to state sponsorship of terrorism, and therefore a prohibited use of force pursuant to the UN Declaration on Friendly Relations. Furthermore, organizing terrorist acts is related to the concept of direction or control in Article 8 of the ILC Articles on State Responsibility. To the extent that a state’s organizational role amounted to either instructions to act or met the threshold level of control under Article 8 of the ILC Articles on State Responsibility, terrorist acts organized by a state would be attributable thereto on that basis and would amount to a prohibited use of force.34

A curious feature of the UN Declaration on Friendly Relations, as interpreted by the International Court of Justice (‘ICJ’), is that state support (assistance) for terrorism will only amount to a prohibited use of force if the modalities of assistance themselves amount to a threat or use of force. For instance, the ICJ held that the arming and training of the contras amounted to a breach of the prohibition of the threat or use of force, while financing the contras did not.35 The distinction must lie in the nature of the support, because the use of force by the non-state actors being supported remains the same, whatever form of support the state provides. The ICJ’s decision implies that support which is necessarily ancillary to a use of force and military in nature will amount to a threat or use of force, while financing (which is perhaps neutral as to the threat or use of force) will not. The difficulty with the ICJ’s distinction is that it misinterprets the UN Declaration on Friendly Relations. ‘[O]rganizing, instigating, assisting or participating in acts of civil strife or terrorist acts in another State or acquiescing in organized activities within its territory directed toward the commission of such acts, when the acts referred to in the present paragraph involve a threat or use of force’ amounts to a prohibited use of force.36 The phrase ‘when the acts referred to in the present paragraph involve a threat or use of force’ qualifies ‘the acts of civil strife or terrorist (p.30) acts in another State’, and not ‘organizing, instigating, assisting or participating’. In the case of terrorism, support (whether military or financial) should therefore amount to a prohibited threat or use of force when the terrorist act itself amounts to such a use of force.37 As the ICJ’s reasoning on this point has not been reconsidered in later judgments,38 it remains the Court’s position that training in military combat tactics and the provision of weapons, weapons systems, or ammunition to non-state actors for the purposes of assisting in the commission of terrorist acts will amount to a prohibited use of force, while financing terrorist acts (or perhaps providing diplomatic or intelligence support) will not.

Finally, the UN Declaration on Friendly Relations requires a state to refrain from passively supporting international terrorism in that states are under a duty to refrain from acquiescing in the commission of terrorist acts in another state.39 While the obligation itself is not framed as a positive duty to act, it will only be complied with through positive action, given that it could be breached through omission or inaction on the part of the state. A state that does nothing in the face of known activities within its territory directed toward the commission of terrorist acts in another state is acquiescing in such activities. A state that takes positive measures to counter such activities is refraining from acquiescing. Given that compliance with the obligation to refrain from acquiescing in terrorist activities requires positive action, it mirrors to a large extent the obligation to prevent terrorism examined in Chapter 3. Indeed, developments in international law following the 9/11 terrorist attacks have led to a rapprochement between the obligation to refrain from acquiescing in terrorism and the obligation to prevent terrorism, as discussed in Section 3.1.3 below.

2.1.3 Non-intervention in the domestic affairs of another state

The UN Declaration on Friendly Relations also considers state terrorism to be a violation of the principle of non-intervention.40 Unlike negotiation of the UN Definition of Aggression, there was virtually no disagreement in the Special Committee on Friendly Relations regarding whether the principle of non-intervention incorporated a prohibition of state terrorism.41 The principle of non-intervention, considered a principle of customary international law by the ICJ,42 stipulates ‘the duty not to intervene in matters within the domestic jurisdiction of any State, (p.31) in accordance with the Charter’.43 The terrorism-specific instantiation of the principle of non-intervention prohibits organizing, assisting, fomenting, financing, inciting or tolerating ‘subversive, terrorist or armed activities directed toward the violent overthrow of the regime of another State, or interfer[ing] in civil strife in another State’.44 While the prohibited purposes of terrorist activities (and a state’s organization, assistance or tolerance thereof) are more circumscribed than those set out in the general formulation of the principle of non-intervention, the prohibition of state terrorism should be interpreted within the broader context of that principle as equally prohibiting state sponsorship or support of terrorist activities with general interventionist aims.

In part, the principle of non-intervention gives rise to the same prohibitions in regard to state sponsorship of or support for terrorism as does the prohibition of the use of force. The distinction lies in the purpose or objective of the terrorist activities being sponsored or supported. Where that purpose or objective is interference with ‘matters in which each State is permitted, by the principle of State sovereignty, to decide freely’,45 then the prohibition on sponsorship of or support for such activities falls within the scope of the principle of non-intervention.46 The requirement of an interventionist purpose, however, does not really serve to restrict the type of terrorist conduct that might fall within the scope of the principle of non-intervention. The prohibited purposes are so broad that the principle of non-intervention has been described as one that can subsume the whole of international law.47

To the extent that a state is sponsoring or militarily supporting terrorist activities (thereby breaching the prohibition of the use of force as understood by the ICJ) and the terrorist activities have as their objective interference in the domestic affairs of another state, the state’s conduct will breach both the prohibition of the use of force and the principle of non-intervention.48 In order to fall within the principle of non-intervention as articulated in the UN Declaration on Friendly Relations, however, a state’s support for terrorism need not itself amount to a threat or use of force. For instance, the ICJ held that US financing of the contras did not amount to a breach of the prohibition of the use of force, although it was an illegal intervention in the (p.32) domestic affairs of Nicaragua.49 By analogy, assistance with diplomatic assets or providing transportation or intelligence, none of which, by themselves, imply a use of force, could amount to a breach of the principle of non-intervention, but not the prohibition of the use of force.

The prohibition of state support for terrorism, as set out in both the prohibition of the use of force and the principle of non-intervention in the UN Declaration on Friendly Relations, is directed at support for the terrorist act, not the terrorist actor.50 This will sometimes be a distinction without a difference, but may involve complicated questions of fact. For instance, providing funds to a particular person or group of persons would not amount to financing terrorist acts unless the financier intended to finance terrorist activities,51 or at least had reasonable notice that such funds were to be used for terrorist purposes.52 Such notice will likely be inferred in many circumstances, for example where it is notorious that the person or group of persons use collected funds to finance terrorist attacks.53 Assume, for example, that a state is providing financial support to Al Qaeda. Al Qaeda is not only known for its terrorist activities, but the subject of sanctions under UN Security Council Resolution 1390 (2002). It could therefore be inferred that the state was providing funds to finance terrorism (and not, for example, to finance medical care or education for Al Qaeda operatives),54 and such conduct could amount to a breach of the customary international law principle of non-intervention. On the basis of the distinction between military and other forms of support set out in the ICJ’s Nicaragua decision, such financing would not, however, amount to a prohibited use of force.55 Likewise, training a group of non-state actors in intelligence gathering, surveillance, use of sophisticated communications (p.33) equipment, explosives etc., does not, in itself, amount to a breach of the obligation to refrain from supporting acts of terrorism (as an instantiation of the general prohibition of the use of force, or, depending on the purpose of the terrorist acts, the prohibition of intervention). Only if the assistance is provided for the purpose of assisting in the commission of terrorist acts is the prohibition of state terrorism engaged. The determination of a state’s purpose in providing assistance will be a question of fact but will generally be inferable from a state’s notice of the non-state actors’ own purposes in seeking or accepting the assistance.56

2.1.4 Conclusion

The prohibition of state sponsorship or support for acts of international terrorism is an instantiation of rules under general international law, in particular the prohibition of aggression, the prohibition of the use of force, and the principle of non-intervention. The analysis above identifies four factors that are relevant to determining which primary rule is breached by a state’s involvement in terrorism. The first factor is the extent to which the terrorist conduct is attributable to the state. The distinction between state sponsorship of and state support for terrorism turns on the application of the secondary rules of state responsibility (examined in Section 2.2 below)—and affects the primary rule that can be engaged by the state’s conduct. The second factor bears on the intensity or gravity of the use of terrorist force (from minor attacks to a use of terrorist force equivalent to an act of aggression). Together, these two criteria determine whether a state’s involvement in a terrorist attack amounts to an act of aggression (as defined in the UN Definition of Aggression) or a prohibited use of force (as set out in Article 2(4) of the UN Charter and the UN Declaration on Friendly Relations). In order that a state’s involvement in terrorism amount to an act of aggression, the terrorist attack must be attributable to the state and be of such gravity as to amount to an act of aggression had it been carried out by the state’s military forces. If the terrorist attack is not grave enough to be characterized as an act of aggression, but is nevertheless attributable to the state, the state’s conduct amounts to a prohibited use of force. The third factor that determines which primary rule is engaged by a state’s sponsorship or support of terrorism bears on the purpose or aim of the terrorist use of force. To the extent that the purpose of terrorist force is an intervention in the domestic affairs of another state, state sponsorship of terrorism (in addition to being an act of aggression or a prohibited use of force) will amount to a prohibited intervention. Where conduct is not attributable to a state, and the state is only supporting (rather than sponsoring) international terrorism, the fourth factor that determines which primary rule is engaged by the state conduct is the form of support. Support that itself amounts to a use of force breaches the prohibition (p.34) of the use of force,57 while other forms of support, to the extent that the aim of the terrorist force is interventionist (very broadly defined), breach the principle of non-intervention.

2.2 Attribution

In order for a state to be held ‘directly’ responsible for the commission of a terrorist act, such act must both be attributable to the state and amount to the breach of an international obligation.58 Section 2.1 above explored the international obligations that might be engaged by a state’s sponsorship of an act of terrorism. A state, however, only acts through natural persons.59 The rules of attribution in Part One, Chapter II, of the ILC Articles on State Responsibility define the circumstances in which the acts of natural persons (whether acting individually or as part of a group or entity) will be considered acts of the state for the purposes of that state’s responsibility.60 The following sections examine the application of the different rules of attribution in the terrorism context, and consider the extent to which these rules are adequate to respond to the threat posed by state participation in acts of international terrorism.

2.2.1 Organs of the state

Under Article 4 of the ILC’s Articles, ‘the conduct of any State organ shall be considered an act of that State under international law’.61 This rule of attribution provides the clearest legal standard for attributing conduct to a state, but its successful application in the terrorism context is complicated by difficulties in situating terrorism within a sphere of legitimate state activity.

It has long been accepted that a state is responsible for the conduct of its organs even if they have exceeded their competence under municipal law or disobeyed instructions (ultra vires conduct), as long as the organ acted in an official capacity.62 (p.35) This rule is articulated in Article 7 of the ILC Articles on State Responsibility. Because ultra vires conduct, by definition, will not be in the actual official capacity of the state organ (but beyond it, while connected to it), official capacity is determined both in reference to the real and apparent authority of a state organ.63 Apparent authority exists when the state organ acts under ‘cover of [its] official character’64 or while ‘cloaked with governmental authority’.65 Effectively, the state is responsible for conduct actually within the official capacity of a particular state organ, and conduct that appears to be within its official capacity to third parties (usually the victims of the relevant conduct) given that the state organ is acting under colour of its official capacity and using tools placed at its disposal by virtue of that capacity. À contrario, the state is not responsible for the conduct of a state organ when that organ acts in a purely private capacity. While the commentaries to the ILC Articles on State Responsibility warn against confusing ultra vires conduct with purely private conduct,66 Special Rapporteurs on State Responsibility have acknowledged that it may be difficult in practice to distinguish conduct exceeding or contravening instructions from conduct that is so far removed from the sphere of the state organ’s official functions that it amounts to private conduct.67 Jurisprudence that addresses the distinction in the context of crimes committed by state organs relies on the cover of official status under which the relevant persons acted: based on the fact that a state organ appeared to be acting within its official capacity, and used the tools at its disposal by virtue of that capacity, the conduct is characterized as official (even if ultra vires) instead of purely private.68

The distinction between ultra vires and purely private conduct is particularly problematic to apply in the terrorism context given that acts of terrorism carried out by state organs will virtually always be in the form of covert operations, carried out by secret service agents who do not display any outward manifestation of the authority under which they act. The state organs will appear to be private citizens, engaging in private conduct. As a result, such acts of terrorism could not be said to have been carried out under colour of authority. A finding of attributability will therefore require holding that, in carrying out acts of terrorism, the state organ was acting in its actual (rather than apparent) official capacity. But such a determination will invariably involve policy judgments as to the proper sphere of state activity. If a court was not (p.36) willing to hold that a terrorist offence fell within the actual official capacity of a state organ, it would have to hold that the conduct was carried out in the private capacity of the state organ, thereby making it unattributable.

The practical difficulties of distinguishing between conduct carried out in an official capacity (but ultra vires) and conduct carried out in a private capacity are illustrated by the Rainbow Warrior case. The ‘Rainbow Warrior’ was a Greenpeace ship, moored in Auckland Harbour, preparing to protest against French nuclear testing in the South Pacific. Shortly before midnight on 10 July 1985, explosive devices attached to the hull of the ‘Rainbow Warrior’ were detonated, blowing an eight-foot wide hole into the ship below the waterline. The ship sank within minutes of the explosion, killing a photographer on board. Two days after the explosion, two French secret service agents were interviewed regarding their role in the destruction of the Greenpeace ship. Alain Mafart and Dominique Prieur were arrested following their interviews.69 France initially denied any official link between the French citizens in New Zealand’s custody and the French government, and offered France’s full co-operation in New Zealand’s investigations into the ‘criminal outrage committed on [New Zealand] territory’.70 France subsequently admitted that Mafart and Prieur were Direction Générale de la Sécurité Extérieure (‘DGSE’) agents, and acknowledged that DGSE agents had been sent to New Zealand to gather intelligence on Greenpeace, but continued to deny responsibility for the explosions aboard the ‘Rainbow Warrior’ on the basis that neither the French government nor the DGSE had ordered the attack.71

To acknowledge that Mafart and Prieur were organs of the state, yet deny responsibility for their conduct, the French government’s argument could only have been that the DGSE agents were acting in their private capacity when they participated in the bombing of the ‘Rainbow Warrior’. Had the question of France’s responsibility been put to an international court, it could not have found that the agents, carrying Swiss passports and posing as tourists,72 were acting under colour of authority. The only basis of attributability would be the organ status of the DGSE agents and a finding that acts of terrorism fell within the sphere of official functions entrusted by the French State to the DGSE. The fact of organ status would certainly have created a presumption of attributability, and it would have been for France to argue that acts of terrorism are not official acts within the meaning of Article 7 of the ILC Articles on State Responsibility. That said, qualifying criminal conduct as falling within the official functions of an organ of the French State would have been a sensitive determination for an international court to make. Under mounting media pressure, however, the French Government acknowledged that the DGSE agents were acting in their actual official capacity. (p.37) Prime Minister Laurent Fabius admitted that the French secret service had ordered the attack on the ‘Rainbow Warrior’ and accepted international responsibility for the attack.73 France and New Zealand could not agree on the amount of compensation to be paid by France, or on the fate of the two secret service agents (who had been convicted of manslaughter in the interim). Both issues were put to the UN Secretary-General for a binding ruling.74

2.2.2 Instructions, direction or control

Notwithstanding the Rainbow Warrior case examined above, acts of international terrorism are rarely carried out by organs of a state. States are more likely to conduct terrorist activities through private persons or groups who act on their behalf while remaining outside the formal structure of the state.75 The applicable standard of attributability is therefore set out in Article 8 of the ILC Articles on State Responsibility, which reads:

The conduct of a person or group of persons shall be considered an act of a State under international law if the person or group of persons is in fact acting on the instructions of, or under the direction or control of, the State in carrying out the conduct.76

Acting on the instructions of a state was first codified as a basis for attributing the conduct of non-state actors to a state in the draft ILC Articles on State Responsibility adopted on first reading,77 and subsequently confirmed by the ICJ in its Tehran Hostages decision.78 The Commentaries to the ILC Articles on State Responsibility highlight that the ‘acting on the instructions of’ standard applies even if the persons involved are private individuals and are not exercising ‘governmental authority’.79 As a result, the practical difficulties involved in distinguishing between official and private conduct under Article 4, particularly in situating (p.38) terrorism within a sphere of legitimate state activity (discussed in Section 2.2.1 above), do not complicate the application of Article 8 in the terrorism context. The Commentaries to the ILC Articles on State Responsibility further describe the application of the ‘acting on instructions’ standard of attribution as applying where:

State organs supplement their own action by recruiting or instigating private persons or groups who act as ‘auxiliaries’ while remaining outside the official structure of the State […including persons] sent as ‘volunteers’ to neighbouring countries, or who are instructed to carry out particular missions abroad.80

The clear implication of the Commentary is that sending volunteers (mirroring the language of Article 3(g) of the UN Definition of Aggression), or instructing volunteers on a particular mission, will fulfil the standard of attribution set out in Article 8 of the ILC Articles on State Responsibility. According to the Commentary, particular instructions on a mission are not required in regard to the sending of volunteers. The ICJ, however, has not interpreted Article 8 in this way. In its Bosnia Genocide Case decision, the Court held that it must be shown that ‘the State’s instructions were given in respect of each operation in which the alleged violations occurred, not generally in respect of the overall actions taken by the persons or groups of persons having committed the violations’.81

Given the improbability of an applicant state being able to prove that terrorist conduct was undertaken on the specific instructions of the respondent state,82 this section focuses instead on state control over non-state actors as a basis for attribution in the terrorism context. It examines the Nicaragua decision, the partial codification of that decision by the ILC, reformulation of the Nicaragua control standard for attribution by the International Criminal Tribunal for the Former Yugoslavia (‘ICTY’) in its Tadić decision, and the ICJ’s reaction to that reformulation in its Bosnia Genocide Case decision.

(i) International jurisprudence and the ILC’s codification of the rules on attribution

In Nicaragua, the ICJ considered the conditions under which the conduct of non-state actors, in particular that of the contras, would be attributable to the US. Nicaragua alleged that the US was responsible for breaching the prohibition of the use of force, the principle of non-intervention, and the duty not to kill, wound or kidnap citizens of Nicaragua, through its active participation in and support for military and paramilitary activities in and around Nicaragua. Before setting forth (p.39) the legal standard for attribution, the ICJ made a number of factual determinations regarding the relationship between the US and the contras. Importantly, the Court determined that the US did not create the armed opposition contra forces, although the size of the contras increased dramatically with its military and financial assistance.83 The Court considered it to have been established that the US financed the contras,84 provided significant logistical support in the form of uniforms (including boots), ammunition, and communications and military equipment,85 supplied the contras with intelligence on the movement of Nicaraguan troops,86 and trained the contras.87 The Court also found that a number of the contras’ paramilitary operations were decided and planned in close collaboration with US advisers,88 and that the US selected targets for the contras’ armed activities.89

There are three levels of potentially attributable conduct raised in Nicaragua: the contras’ paramilitary campaign in general; specific paramilitary operations; and humanitarian law violations committed during the course of specific paramilitary operations. The ICJ considered the attributability of the contras’ paramilitary campaign en bloc to turn on the de facto organ status of the contras. Had the contras amounted to a de facto organ of the US, the US would have been directly responsible for all their activities, including humanitarian law violations committed by the contras in the course of some of their paramilitary operations. But the ICJ concluded that the level of US involvement in the contras’ activities did not signify that ‘the relationship of the contras to the United States Government was so much one of dependence on the one side and control on the other that it would be right to equate the contras, for legal purposes, with an organ of the United States Government, or as acting on behalf of that Government’.90 As a result, the ICJ did not consider the contras’ paramilitary campaign as a whole to be attributable to the US.

The second level of potentially attributable conduct the ICJ might have considered relates to specific and identifiable paramilitary operations, for instance the targeting of a particular military installation. Nicaragua’s pleadings addressed the contras’ use of force on an operation by operation basis,91 but did not break (p.40) down US support for the operations in the same manner. Instead, the pleadings addressed US support for the contras’ activities in a general manner, without tying such support to specific paramilitary operations.92 The ICJ did not formulate a standard for attribution in relation to specific paramilitary operations, and regarded the US to have violated the prohibition of the use of force based on its own conduct vis à vis the contras (i.e. training and arming the contras),93 rather than on the basis of the attributability of specific paramilitary operations.94

The third level of potentially attributable conduct in Nicaragua is in relation to the humanitarian law violations committed during the course of particular paramilitary operations. The ICJ elaborated an ‘effective control’ standard as the relevant basis for attribution, and held that general control over paramilitary forces and operations, such as that exercised by the US over the contras, was not sufficient for the purposes of attributing the humanitarian law violations.95 While the ICJ acknowledged that the US selected military and paramilitary targets for the contras and planned its operations, it held that these elements did not necessarily imply that the US ‘directed and enforced the perpetration of the acts contrary to human rights and humanitarian law’ committed by the contras during the course of those operations.96 The ICJ held that:

such acts could well be committed by members of the contras without the control of the United States [and that for] such acts to give rise to the legal responsibility of the United States, it would in principle have to be proved that the State had effective control of the military and paramilitary operations in the course of which the alleged violations were committed.97

The ICJ’s decision in Nicaragua was considered by both the Trial Chamber and Appeals Chamber of the ICTY in their Tadić decisions.98 In determining which body of humanitarian law applied to the case, the Trial Chamber relied on the rules of state responsibility, in particular the rules of attribution, to decide whether the conflict in Bosnia was of an international or non-international character. The Trial Chamber adopted the ‘effective control’ test set out in the ICJ’s Nicaragua decision, and held that the Former Republic of Yugoslavia (‘FRY’) did not exercise effective control over the Bosnian Serb forces (‘VRS’). As a result, the Trial Chamber held that the VRS military campaign in Bosnia could not be attributed to the FRY and that the FRY could not be considered a party to the conflict on that basis—thereby (p.41) rendering the conflict non-international for the purposes of applicable humanitarian law.99 The Prosecutor appealed the decision, and argued that ‘[i]t would lead to absurd results to apply the rules relating to state responsibility to assist in determining’ which body of humanitarian law applied to the conflict.100 The Appeals Chamber, however, upheld the Trial Chamber’s approach to the issue, and held that:

[i]nternational humanitarian law does not contain any criteria unique to this body of law for establishing when a group of individuals may be regarded as being under the control of a State, that is, as acting as de facto State officials. Consequently, it is necessary to examine the notion of control by a State over individuals, laid down in general international law, for the purpose of establishing whether those individuals may be regarded as acting as de facto State officials.101

Having determined that the general law of state responsibility was applicable in the circumstances, the ICTY Appeals Chamber rejected the Nicaragua ‘effective control’ test as the only control-based test for attributing non-state military operations to a state. The Appeals Chamber drew a distinction between the level of control to be exercised over private individuals or unorganized groups of individuals and that to be exercised over militarily organized groups. In regard to the latter, the Appeals Chamber held that it is by no means necessary that the controlling state should plan all the operations of the military units dependant on it, choose their targets or give specific instructions on military operations (amounting to effective control over those operations) in order that those operations be attributable to the state. Instead, the Chamber held that ‘overall control’, which exists where the state has a role in organizing, coordinating or planning the military operations of a group, in addition to financing, training, equipping or providing operational support for such military operations, is sufficient for the purposes of attribution.102 Whether or not the ICTY correctly relied on the rules of state responsibility to determine the applicable humanitarian law,103 its decision is of interest in that it addresses the relevant standard of attribution for particular military operations, without regard for whether humanitarian law violations were committed in the course thereof.

Following the decision in Nicaragua, Special Rapporteur Crawford revised Article 8 of the ILC Articles on State Responsibility, incorporating a control standard, but without specifying the threshold of control that it required.104 The Commentaries to Article 8 note that the ICJ addressed the relevant degree of (p.42) control in Nicaragua and highlight the ‘effective control’ standard elaborated in that decision.105 The Commentaries do not, however, limit the standard of control in Article 8 to the Nicaragua effective control test. Although critical of the ICTY Appeals Chamber’s foray into the law of state responsibility, the Commentaries to Article 8 do not reject the ‘overall control’ test set out in Tadić, acknowledging that ‘[i]n any event it is a matter for appreciation in each case whether particular conduct was or was not carried out under the control of a State, to such an extent that the conduct controlled should be attributed to it’.106

The ICJ, however, has not adopted such a flexible approach to the standard of control articulated in Article 8 of the ILC Articles on State Responsibility. In its Bosnia Genocide Case decision, the ICJ reprimanded the ICTY Appeals Chamber for its incursion into the law of state responsibility107 and rejected the ‘overall control’ test for attribution set out in the Tadić Appeals Chamber decision as ‘stretch[ing] too far, almost to breaking point, the connection which must exist between the conduct of a State’s organs and its international responsibility’108 (albeit without explaining why this should be so). The Court instead reaffirmed the ‘effective control’ standard first set out in Nicaragua. Indeed, the Court held that Article 8 of the ILC Articles on State Responsibility must be ‘understood in the light of the Court’s jurisprudence on the subject, particularly [its decision in Nicaragua]’,109 rendering ‘effective control’ the exclusive standard of control under Article 8.110 Whether that is appropriate, particularly in the context of state responsibility for terrorism, remains to be considered below.

(ii) Article 8 of the ILC Articles on State Responsibility in the terrorism context

Commentators who regard the ‘effective control’ test as too strict for the purposes of addressing state terrorism have broadly supported a reading of Article 8 of the ILC Articles on State Responsibility that leaves room for a flexible adaptation of the standard of control.111 Some states have also read Article 8 in a way that leaves room for such flexible adaptation. For instance, the Netherlands has suggested that the words ‘direction or control’ in Article 8 of the ILC Articles on State Responsibility allow for the application of both a strict standard of ‘effective control’, as used by the ICJ in Nicaragua, and a more flexible standard as applied by the Appeals (p.43) Chamber of the ICTY in its Tadić decision. In its view, this inbuilt ambiguity is a positive element and offers scope for progressive development of the legal rules on state responsibility.112 In addition, members of the ILC, when endorsing Special Rapporteur Crawford’s formulation of Article 8, suggested that varying degrees of sufficient control were required in different legal contexts.113 Such flexible approaches to ‘control’ under Article 8 of the ILC Articles on State Responsibility have in fact been adopted in other judicial dispute settlement contexts.114

The difficulty with ‘effective control’ as the only applicable control threshold is that the standard, as adopted by the ICJ in Nicaragua, was driven by the particular facts of the case. In Nicaragua, the ICJ was dealing with two separate levels of activity: the first was the paramilitary operations of the contras (which the Court did not consider separately for the purposes of attribution); the second level of activity involved violations of humanitarian law perpetrated in the course of those paramilitary operations. The humanitarian law violations, however, were a non-inherent feature of the military operations of the contras, and the ICJ’s ‘effective control’ test is formulated to ensure that responsibility for such violations only arises where a state’s control extends to those non-inherent features of a military campaign. In the terrorism context, however, there is no second level of activity—the breach of international law is inherent in terrorist operations. Contrary to the case in Nicaragua, it is difficult to argue that material military support (including logistical, munitions, and military training) for terrorist activities does not necessarily imply support for the offences committed by the terrorists in the course of their use of force.115 There is therefore no need for the added layer of effective control, in addition to a more general level of control over the group’s operations (through its support thereof), to ensure that a state is only held responsible for that over which it exercised sufficient control.

Special Rapporteur Crawford recognized that the decision in Nicaragua related specifically to the extent of the obligation of the state to control irregular forces or (p.44) auxiliaries acting under its auspices and that it might present a lex specialis in the context of the rules of attribution. He concluded, however, that it is not clear why conduct of auxiliary armed forces in operations under specific direction or control should be attributable to the state, but not analogous conduct under state direction and control in other spheres.116 The question Special Rapporteur Crawford might have asked is whether there are any circumstances in which a lower threshold for attribution might be appropriate, particularly given that the added measure of control injected into the attribution test for the purposes of the ICJ’s decision in Nicaragua seems unnecessary in the terrorism context, or indeed in any other context where the operation is itself an offence defined under international law.117

However unsuitable the ‘effective control’ standard might be to the terrorism context, the Bosnia Genocide Case decision does suggest that the ICJ will nevertheless apply it when considering the attributability of non-state conduct to a state. That said, the facts of the Bosnia Genocide Case are not dissimilar from those in Nicaragua. The VRS were fighting a civil war—and genocide is a non-inherent feature of civil wars. As a result, the Court reaffirmed the applicability of the standard of control it first established in Nicaragua, in reference to the attributability of non-inherent features of military campaigns. Were the Court confronted with a state’s overall control of a terrorist campaign, it might well realize that a different threshold of control is sufficient for the purposes of attributing inherent features of a use of force. This would be particularly important because state support for terrorism, no matter how substantial, will not generally satisfy the ‘effective control’ test. In his study of state terrorism, Byman concludes that the most common forms of support for non-state terrorist actors are training (in explosives particularly), the provision of intelligence, the supply of arms, financing, the provision of logistical assistance (for example issuing passports and helping terrorist actors obtain visas through state-fronted companies or non-governmental organizations), ideological direction and sanctuary.118 While states often support terrorist activities by offering several or indeed all these forms of support,119 together they do not amount to effective control over particular terrorist operations, even if the state chooses the target of the terrorist operation. But states do not necessarily exercise operational control over terrorist attacks that are committed on their behalf, which is what the ‘effective control’ standard of attribution would require. It would be more accurate to consider state sponsorship of terrorism as based on a general control over terrorist operations (including the selection of targets). Such control would satisfy the ‘overall control’ test articulated in the ICTY Appeals Chamber’s decision in Tadić. Were the flexible approach to Article 8 advocated by states and ILC members adopted, it could incorporate the ‘overall control’ standard as a basis of attribution, and thereby respond to the particularities (p.45) of the terrorism context in a way that rigid adherence to the Nicaragua standard does not.

2.2.3 Complicity revisited

The sections above examine the broadly accepted bases of attribution reflected in the ILC Articles on State Responsibility, as they apply in the terrorism context. The sufficiency of those grounds of attribution has recently been challenged in academic commentary on the basis of state practice in the jus ad bellum context. This section examines the extent to which this challenge is justified and the implications, if any, of proposed changes to the rules of attribution applicable in the terrorism context. The contested territory on the rules of attribution centre on concepts of complicity or acquiescence—which occupy the boundary between ‘direct’ and ‘indirect’ responsibility.

If conduct is not attributable to a state on the basis of the rules of attribution set out in the ILC Articles on State Responsibility (including on the basis of organ status, or instructions, direction or control, as examined in Sections 2.2.1 and 2.2.2 above), the state can only be held responsible for its own wrongdoing in relation to that private conduct.120 This lends itself to a clear distinction between a state’s ‘direct’ responsibility for a terrorist attack (in virtue of that attack being attributable to the state) and a state’s ‘indirect’ responsibility for breach of its obligations in relation to a terrorist attack—including obligations to refrain from supporting terrorism, to act in prevention of acts of terrorism, and to extradite or submit terrorist actors to prosecution—without the state being responsible for the terrorist attack itself. In the latter case, particularly as regards the obligations to prevent terrorism and to extradite or submit terrorist actors to prosecution,121 the private terrorist conduct is not the basis of responsibility in the sense implied by attribution. Rather, the private terrorist conduct is the catalyst for the state’s responsibility,122 in that it triggers the state’s obligation to act, failure of which constitutes the internationally wrongful act.

The distinction between ‘direct’ responsibility for attributable conduct, and ‘indirect’ responsibility for failures to act in anticipation of or in response to conduct not attributable to a state, was not always clear. In the late nineteenth and early twentieth centuries, states were held ‘directly’ responsible for private conduct (in the sense implied by attribution) based on their complicity or acquiescence therein—put in evidence through a failure to prevent or punish the private conduct.123 This artificial way of linking private conduct to the state, rather than focusing on whether the state had an independent obligation to prevent or punish the conduct,124 was gradually abandoned in the inter-war (p.46) period.125 The ILC and international jurisprudence have since firmly rejected complicity or acquiescence in private conduct as a basis of attribution.126 Nevertheless, complicity-based theories of attribution are not dead: recent state practice, coupled with a reading of the ICJ’s jurisprudence that suggests a strict attribution-based definition of ‘armed attack’ under Article 51 of the UN Charter, have breathed new life into them.

The state practice on complicity or acquiescence as a basis for attribution in the terrorism context that is treated as relevant in the literature derives generally from states’ recent exercise of their right to use force in self-defence against non-state terrorist actors. The scope of the right to use force in self-defence is set out in Article 51 of the UN Charter, which reads in relevant part that ‘[n]othing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations’.127 A use of force in self-defence is therefore only legitimate under the Charter to the extent that it is in response to an armed attack.128 The ICJ’s jurisprudence has been interpreted as limiting ‘armed attacks’ to uses of force by or attributable to a state.129 On the basis of such a definition, defensive force in response to a terrorist attack emanating from foreign territory would only be legitimate under Article 51 of the UN Charter if the (p.47) attack130 were carried out by the territorial state’s organs or if it were otherwise attributable to the state from whose territory it emanated (and in whose territory defensive force was used).

The difficulty with a strict attribution-based definition of ‘armed attack’ is that it fails to account for recent uses of defensive force in response to terrorist attacks carried out by non-state actors (that were not attributable to the state on the basis of the ILC Articles on State Responsibility or Article 3(g) of the UN Definition of Aggression) that were widely accepted as legitimate by the international community, most particularly the US-led coalition military campaign in Afghanistan in 2001 (‘Operation Enduring Freedom’). In order to square the legitimacy of Operation Enduring Freedom against a strict attribution-based reading of ‘armed attack’, scholars have been forced into the uncomfortable position of having to resuscitate old bases for attributing non-state conduct to the state in whose territory force was used defensively, including complicity in terrorist activities or harbouring terrorists,131 or to deny the legality of the defensive force based on the non-attributability of the relevant terrorist attacks to Afghanistan (and its de facto Taliban government), despite the overwhelming international support it received.132 Neither of these solutions is satisfactory. The first one reinvigorates a standard of attribution that has long been rejected as too tenuous a basis for direct responsibility. The second ignores the facts to maintain legal coherence.133

Implicit in the view that complicity is a basis of attribution is the argument that any change to the rules of attribution that are necessary to respond to the security context will be carried through to the law of state responsibility.134 But there is no good reason why the rules of attribution, as they may or may not need to develop for the purposes of defining the limits of the right to use force in self-defence, would also need to develop for the purposes of holding a state delictually responsible. Indeed, any changes to the rules of attribution that may be necessary to address state practice under Article 51 of the UN Charter would best be characterized as lex specialis.

Even if, however, changes in the rules of attribution in the jus ad bellum context were generalized for the purposes of state responsibility, the view that complicity has re-emerged as a basis of attribution (on the grounds of post-9/11 jus ad bellum practice) is rooted in a misinterpretation of the ICJ’s jurisprudence and the relevant state practice. This section examines both, and argues that a careful reading of the ICJ’s jurisprudence, coupled with the increasing recognition of a right to use force (p.48) in self-defence against non-state terrorist actors in foreign territory, alleviates the need to play ‘fast and loose’ with the rules of attribution or to ignore the acknowledged legitimacy of certain recent defensive operations.

(i) Rejection of an attribution-based definition of ‘armed attack’

Uses of force in self-defence against non-state terrorist actors can take two separate forms. The first involves a use of force that only targets the non-state actors and their bases of operation in foreign territory. The second is where the use of force equally, or perhaps only, targets the state from whose territory the non-state actors operate. A majority of the ICJ has consistently held that a use of defensive force in response to an attack by non-state actors is a legitimate exercise of rights under Article 51 of the UN Charter if (and only if) the armed attack is attributable to the state in whose territory defensive force is used. The ICJ’s insistence on the attributability of an armed attack, however, can be explained by the distinction set out above. In both the contentious cases addressing the right to use force in self-defence against non-state actors, the use of force was not directed solely at the non-state actors alleged to have launched armed attacks—it was equally (if not exclusively) directed at the state from whose territory the non-state actors operated. The fact that the ICJ required armed attacks launched by non-state actors to be attributable to the state in whose territory defensive force was used may thus be understood as a direct consequence of the fact that the territorial state was itself the target of defensive force. The ICJ’s refusal to address the circumstances under which a state has a right to use force in self-defence against (and only against) non-state actors, however much lamented in the separate opinions,135 is therefore justified on the facts of each case and should not be read as precluding such uses of defensive force.

In Nicaragua, the ICJ considered whether US assistance to the Nicaraguan contra forces136 amounted to a legitimate exercise of the right of collective self-defence. The US claimed to be acting (primarily) in defence of El Salvador, which was the victim of armed attacks by rebel groups allegedly supplied with arms through Nicaragua with the active support, or at the very least complicity, of the Nicaraguan Government.137 The contras’ main targets were Sandinista troops, although there were numerous reports of attacks on non-combatants138 and Nicaragua alleged a US-devised strategy for the contras to attack ‘economic targets like electrical plants and storage facilities’ in Nicaragua.139 The ICJ noted that, to defend El Salvador (p.49) against rebel attacks, the US might have arranged for a strong patrol force in El Salvador along its frontiers with Nicaragua, and that ‘it is difficult to accept that [the US] should have continued to carry out military and paramilitary activities against Nicaragua if their only purpose was, as alleged, to serve as a riposte in the exercise of the right of self-defence’.140 Given that the US-supported contras were directly targeting the Nicaraguan Government and military, the circumstances under which a state could legitimately use force against non-state actors (and only against non-state actors) in foreign territory was not in issue. Furthermore, the conditions under which a state could use force against another state in response to armed attacks by non-state actors were not met. The ICJ held that the legitimate exercise of the right of self-defence required that an armed attack by rebel groups be attributable to the state against which defensive force was used.141 But Nicaragua’s alleged assistance to rebel groups (in the form of provision of weapons and logistical support) did not meet the threshold for attributing the conduct of those groups to Nicaragua,142 and such support did not itself amount to an armed attack.

In its Palestinian Wall Advisory Opinion, the ICJ gave brief consideration to whether Israel’s construction of a security wall within the Occupied Palestinian Territories might be justified as a measure of self-defence. The ICJ considered Israel’s justification for the construction of the wall to be one based on the right of states to defend themselves against terrorist attacks under Article 51 of the UN Charter, as recognized in Security Council Resolutions 1368 (2001) and 1373 (2001). But the Court held that:

Article 51 of the Charter […] recognizes the existence of an inherent right of self-defence in the case of armed attack by one State against another State. However Israel does not claim that the attacks against it are imputable to a foreign State.143

While the Court might be understood as reaffirming the position it took in Nicaragua that armed attacks giving rise to the right of self-defence must be attributable to a foreign state, it might also be understood as merely articulating the conditions for the applicability of Article 51 of the UN Charter. In particular, Article 51 serves to justify a use of force that would otherwise be inconsistent with Article 2(4). As the Court considered the West Bank to be occupied territory, Israel’s use of force in the West Bank (ignoring for the moment that building a wall does not in fact amount to a use of force) could not engage the Article 2(4) (p.50) prohibition which only applies as between sovereign states, thereby rendering Article 51 inapplicable. The ICJ also took a narrow approach to the applicability of Security Council Resolutions 1368 (2001) and 1373 (2001), and held that the territories from which terrorist attacks were launched were under Israeli control and could therefore not be considered in the context of resolutions that addressed the 9/11 terrorist attacks, where attacks were directed from abroad.144 The Court’s refusal to genuinely engage the justification of self-defence has subjected it to severe criticism,145 but is arguably defensible based on the occupied status of Palestinian Territories and the availability of an alternative legal framework within which to assess Israeli conduct. In addition, the legal difficulty regarding a state’s right to use defensive force directly against non-state actors in foreign territory results from the apparent irreconcilability of a state’s right to defend itself and the inviolability of the territorial state’s sovereignty. In the Israeli/Palestinian context, given the occupied status of the territory from which terrorist attacks are launched, the ICJ could not have shed any light on this issue in its decision.

In DRC v. Uganda, the ICJ held that the attacks carried out by rebel groups operating from the DRC’s territory against Uganda were ‘non-attributable to the DRC’,146 and because the legal and factual circumstances giving rise to a right to use force in self-defence were not satisfied, ‘there [was] no need to respond to the contentions of the Parties whether and under what conditions contemporary international law provides for a right of self-defence against large-scale attacks by irregular forces’.147 The ICJ reaffirmed its position, taken in Nicaragua, that a state’s sending armed bands into another state, within the meaning of Article 3(g) of the UN Definition of Aggression, amounts to an armed attack giving rise to the right of self-defence against the sending state.148 The Court did not elaborate on the standard of ‘sending of armed bands’ as a basis for attribution because it did not consider there to be ‘satisfactory proof of the involvement in [the attacks by anti-Ugandan rebel forces against Uganda], direct or indirect, of the Government of the DRC’.149 The ICJ’s insistence that armed attacks be attributable to a state before they can give rise to a right to use force in self-defence, however, has to be (p.51) understood in the context of its findings of fact. The ICJ emphasized that Uganda’s defensive measures were carried out against the DRC,150 particularly noting the fact that Ugandan military action was directed largely against towns and villages far removed from the territory from which anti-Ugandan rebels operated.151 One should therefore read the ICJ’s decision as reflecting the distinction set out above between force used in self-defence against the territorial state (which would require that the armed attacks being responded to are attributable to that state), and force used in self-defence directed against non-state actors within the territorial state, while expressly refusing to address the conditions under which the latter use of force would be permissible. The ICJ’s opinion should not be read as ruling out uses of defensive force in foreign territory that exclusively target non-state actors.

(ii) State practice

Broad support for the Operation Enduring Freedom military campaign in 2001 and subsequent state practice suggests that, if it ever was established, a strict attribution-based definition of ‘armed attack’ no longer is.152 In particular, post-9/11 practice confirms that a use of force directly targeting non-state terrorist actors who have launched an armed attack is a legitimate exercise of the right of self-defence. Operation Enduring Freedom, however, targeted both non-state terrorist actors and the Taliban regime (in their capacity as de facto Government of Afghanistan). As such, in addition to using defensive force directly against non-state terrorist actors (consistently with an increasingly recognized right to do so, and not inconsistently with the reading of the ICJ’s jurisprudence suggested above), the 2001 military campaign in Afghanistan was a broadly supported use of force directed against a state, in response to an armed attack by non-state actors whose conduct is not attributable to that state on the basis of the ILC-sanctioned rules of attribution. The widely accepted legitimacy of the operation therefore raises the question whether, post-9/11, complicity is re-emerging as a basis on which to attribute non-state terrorist conduct to a state. This section examines the state practice as a means of evaluating the possibility that 9/11 was a turning point in international law on the use of force and the rules of attribution as applied in the jus ad bellum context.

In response to the 1998 terrorist attacks on its embassies in Tanzania and Kenya, the US attacked terrorist training camps in Afghanistan and a pharmaceutical plant in Sudan. In a letter dated 20 August 1998 to the Security Council, the US claimed to have been exercising its right of self-defence. The US noted that its use of force was only directed against installations and training camps used by the Bin Laden organization and was ‘carried out only after repeated efforts to convince the Government of the Sudan and the Taliban regime in Afghanistan to shut (p.52) these terrorist activities down and to cease their cooperation with the Bin Laden organization’.153 The US charged the Taliban and Sudan with acquiescing in Bin Laden’s terrorist activities, and based its right to specifically target non-state actors in foreign territory on an inability to rely on the host states’ counter-terrorism efforts. The international community widely condemned the attacks in Sudan—primarily based on an absence of evidence that the pharmaceutical plant was used for anything other than civilian purposes.154 There was no similar condemnation of the use of force in Afghanistan, which was directed solely against Al Qaeda facilities, and not against the Taliban.155 The failure to condemn should not necessarily be viewed as indicating broad support for the US military operation.156 But given past practice of complaining to the Security Council, the absence of condemnation is significant and signals the beginning of the emerging consensus that uses of force specifically targeting non-state terrorist actors, in response to armed attacks they launch from foreign territory, is a legitimate exercise of the right of self-defence.

Operation Enduring Freedom, launched in response to the 9/11 terrorist attacks, targeted Al Qaeda (non-state terrorist actors) operating from Afghan territory. The US and coalition military operations equally targeted the Taliban (Afghanistan’s de facto Government). The US, in its letter to the Security Council dated 7 October 2001, informed the Council that it had:

initiated actions in the exercise of its inherent right of individual and collective self-defence following the armed attacks that were carried out against the United States on 11 September 2001[…]. The attacks on 11 September 2001 and the ongoing threat to the United States and its nationals posed by the Al-Qaeda organization have been made possible by the decision of the Taliban regime to allow the parts of Afghanistan that it controls to be used by this organization as a base of operation […]. In response to these attacks, and in accordance with the inherent right of individual and collective self-defence, United States armed forces have initiated actions designed to prevent and deter further attacks on the United States. These actions include measures against Al-Qaeda terrorist training camps and military installations of the Taliban regime in Afghanistan.157

(p.53) The Security Council is widely considered to have endorsed and even invited the US position that the 9/11 terrorist attacks gave rise to the right to use force in self-defence.158 In particular, Security Council Resolution 1368 condemned the 9/11 terrorist attacks and ‘[r]ecogniz[ed] the inherent right of individual or collective self-defence in accordance with the Charter’.159 Both NATO and the Organization of American States, which at their inception required armed attacks to be attributable to a state before force in self-defence would be justified,160 invoked their collective security arrangements in response to the 9/11 terrorist attacks.161 States informing the Security Council of measures taken in Afghanistan in exercise of the collective right of self-defence emphasized that uses of force were directed against both Al Qaeda bases and the Taliban which supported and harboured Al Qaeda (but not against the Afghan people or Islam).162 Unlike the military campaign in 1998, states invoking the right of self-defence viewed both Al Qaeda and the Taliban as legitimate targets of defensive force.163 If we accept the interpretation of the ICJ’s decisions in Nicaragua and DRC v. Uganda suggested above—namely that they do not preclude uses of defensive force targeted exclusively at non-state terrorist actors, but that attributability will be required if the territorial state is itself the target of defensive force—then the targeting decisions in the 2001 US-led campaign appear to support the argument that a state’s acquiescence in (or harbouring of) terrorist actors operating from its territory was accepted as a basis for attributing the 9/11 terrorist attacks to Afghanistan.164 Some authors have argued that support for targeting the Taliban in 2001 is indeed based on the attributability of the 9/11 terrorist attacks, but reject acquiescence as the basis of attribution. Rather, they argue that the close relationship between Al Qaeda and the Taliban, and the Taliban’s support for Al Qaeda, forms the basis for attribution.165 These arguments, while correctly refusing to stretch the grounds on which conduct will be attributable to a state, do not (p.54) account for the fact that states invoking the right of collective self-defence emphasized the Taliban’s acquiescence in (not support for) Al Qaeda’s terrorist activities.166 It is also unlikely that the Taliban’s refusal to accede to US and Security Council demands to surrender Bin Laden167 amounts to a post facto adoption of Al Qaeda’s conduct for the purposes of attribution. The Taliban made it clear that the refusal to surrender Bin Laden was based on Muslim customs, and did not imply acknowledgment or adoption for the purposes of perpetuating terrorist conduct, as would be required under Article 11 of the ILC Articles on State Responsibility.168

In the post-9/11 world, Operation Enduring Freedom remains the only case in which the international community accepted a state’s right to use force in self-defence against both non-state terrorist actors and the state from whose territory such terrorist actors operated, when the terrorist attack being responded to was not attributable to the territorial state. Subsequent invocations of the right to use defensive force in response to terrorist attacks have been limited to the use of force exclusively targeting non-state terrorist actors.

For instance, following a terrorist attack on a café in Haifa in 2003, Israel launched a guided missile attack in Syrian territory, targeting what it claimed to be a terrorist base used by a Syrian and Iranian sponsored terrorist group (Islamic Jihad) responsible for terrorist attacks against Israel (including the Haifa café attack).169 Following the example of the 1998 and 2001 US military campaigns in Afghanistan, Israel accused Syria of complicity in terrorist attacks by Islamic Jihad, but was very careful to emphasize that its military operation was directed specifically at the Ein Saheb terrorist base.170 The Security Council considered the matter following letters of complaint by Syria171 and Lebanon.172 Despite Islamic Jihad being recognized as a terrorist organization by the EU,173 EU member states condemned Israel’s military response to the Haifa bombing,174 as did most other states appearing before the Security Council.175 The Secretary-General condemned both the Israeli attack in Syria and the preceding terrorist attack in Haifa.176 While the expressions of condemnation before the Security Council have been interpreted (p.55) as an absence of general support for a wide right to use force against terrorist training camps in foreign territory,177 this is not necessarily the lesson to be drawn from the condemnations. Most states firmly situated their comments on the terrorist attack in Haifa and the Israeli response thereto within the broader framework of the Middle East peace process. Their expressions of condemnation were based on the effect both attacks would have on the implementation of the Road Map devised by the Quartet, which was released in between the attack in Haifa and Israel’s military campaign in Syria.178 None of the delegations making presentations before the Security Council addressed the legality of defensive force specifically targeting terrorist bases in foreign territory given an inability to rely on that state to prevent terrorist operations planned or launched from its territory.

In July 2006, Hezbollah abducted two Israeli soldiers and launched a number of rockets from southern Lebanon into northern Israeli towns. In response, Israel launched a large-scale military campaign against Hezbollah in Lebanese territory. As has been Israel’s consistent practice, it claimed not to be acting against the territorial host state, but primarily against non-state terrorists.179 The scale of Israel’s use of force in Lebanese territory, particularly as regards the destruction of all three runways at Beirut International Airport180 and the significant number of civilian deaths,181 militated against broader acceptance of Israel’s characterization of its defensive measures.182 Nevertheless, Israel consistently maintained that it was targeting Hezbollah strongholds or weapons delivery routes, and that any civilian casualties were the result of Hezbollah’s practice of using civilians as human shields.183 A majority of Security Council members recognized Israel’s right to defend itself.184 Given the non-attributability of Hezbollah’s conduct to Lebanon, such recognition amounts to acceptance of a right to use force in self-defence against non-state actors. These states also underlined the need for Lebanon to extend its exclusive control over all of its territory and to act in prevention of (p.56) Hezbollah’s attacks against Israel.185 Taken together, these positions accept that defensive force in foreign territory against non-state actors is sometimes necessary given the host state’s failure (rather than its unwillingness)186 to prevent its territory from being used as a base for terrorist operations.187 All but one of the states recognizing Israel’s right to act in self-defence also characterized Israel’s use of force in July 2006 as disproportionate or excessive,188 referencing Israel’s use of force beyond its immediate border region with Lebanon (from which Hezbollah operated).

Turkey has long claimed a right to resort to measures that are imperative to its own security, including uses of force directed against Kurdistan Workers Party (‘PKK’) non-State actors operating from Iraqi territory. Turkey based its right to use force in foreign territory on its inability to rely on Iraq to control its northern border and prevent cross-border terrorist attacks.189 Turkey undertook military operations against PKK training bases in Iraq in January 1994,190 March 1995,191 and again in May and September of 1997.192 Consistent with earlier approaches to an attribution-based definition of ‘armed attack’, Turkey’s right to respond to PKK attacks (which were not attributable to Iraq) with force in Iraqi territory was not broadly supported.193 More recently, however, the international community has (p.57) softened to the Turkish position. Between the summer and fall of 2007, high level discussions were held between Turkish, Iraqi and US delegates, in which the latter two promised to significantly step up efforts to prevent PKK cross-border attacks.194 Turkey rejected the proposals as inadequate,195 and in response to an escalation in PKK violence across the Iraqi–Turkish border196 began its largest military campaign to date, targeting PKK bases in December 2007.197 Turkey maintained throughout that it was exclusively targeting the PKK and other terrorist targets,198 and avoided claiming a broader right to use force against Iraq’s autonomous Kurdish region or Iraq itself. The international response to the campaign has not been entirely supportive, largely based on the impact thereof on the precarious peace and security situation in the region.199 Iraq initially characterized the use of force as a violation of its sovereignty,200 but subsequent statements by its foreign minister suggest that, to the extent that Turkey asserts a right to defend itself against PKK attacks, the right must be limited to PKK targets—and that civilians and civilian infrastructure should be left untouched.201 Similarly, the US acknowledged that it was warned of the December 2007 Turkish military operation, and claimed to have urged Turkey to limit its action to precise targeting of PKK targets.202 The attitudes of Iraqi and US authorities implicitly acknowledge a right to use force in foreign territory against non-state terrorist actors, while rejecting uses of force against the territorial state in cases of non-attribution. In June 2010, Turkey again attacked PKK insurgents (and only PKK insurgents) in Iraqi territory in response to their attacks on its border forces, without any official reaction from the Iraqis or US.203

On 1 March 2008, Colombia launched a targeted military operation against a Colombian Revolutionary Armed Forces (‘FARC’) training camp in Ecuador, two miles from the Colombian border.204 The raid, while limited to FARC targets, was immediately condemned by Ecuador, followed by Venezuela, each of which broke (p.58) off diplomatic ties with Colombia.205 Colombia claimed to be acting in self-defence, and partly invoked Ecuadorian (and Venezuelan) support for FARC as justification for its violation of Ecuadorian sovereignty.206 The matter was put to an emergency ministerial level meeting at the Organization of American States, which adopted a resolution recognizing every state’s right to defend itself, but positioning the right in the context of the principles of sovereignty and non-intervention. The resolution considered that Colombia’s incursion constituted ‘a violation of the sovereignty and territorial integrity of Ecuador and of principles of international law’,207 for which Colombia issued an apology.208 The swift South American condemnations and Colombian apology, both of which took place in the broader context of the inter-American system, highlight the lack of a broad acceptance, on the facts, that Ecuador is supporting FARC. Nevertheless, Colombia’s assertion of its right of self-defence against non-state terrorist actors in foreign territory is consistent with other assertions of the right, and had some support in the international community.209

(iii) Complicity in terrorism

All invocations of the right to use force in self-defence against terrorist attacks since the 2001 US-led campaign in Afghanistan purport to be based on a right to use defensive force against non-state terrorist actors.210 In each case, the victim state has accused the territorial state of acquiescence or complicity in, or active support for, the terrorist attacks emanating from its territory, but has not claimed a right to also use force directly against the territorial state (as distinguished from in the territorial state’s territory, but against non-state actors). While the 2003 Israeli campaign was criticized, largely in the context of its negative impact on the Middle East peace process, the right to use force in foreign territory in a targeted and proportionate (p.59) manner against non-state actors was recognized in Israel’s 2006 campaign. Equally, Turkey’s right to use force directly against PKK terrorist actors in Iraqi territory was implicitly recognized by Iraq and the US, the most immediately interested states. This state practice strongly supports the argument that, despite the ICJ’s failure to engage the issue, there is a right under international law to use force directly against non-state terrorist actors operating from foreign territory. An attribution-based reading of ‘armed attack’ under Article 51 of the UN Charter should therefore be laid to rest.

The only role a state’s complicity with, or acquiescence in, international terrorism plays in evaluating whether there is a right to use force in self-defence against non-state actors in foreign territory is that it responds to the requirement that the use of force be necessary, given an inability to rely on the host state to prevent its territory from being used as a base for terrorist operations.211 In cases where a state is acting diligently to prevent the terrorist activities of non-state actors operating from its territory, in compliance with its obligation to prevent international terrorism examined in Section 3.1 below, a victim state’s use of force against non-state actors in that state’s territory (amounting to a violation of that state’s territorial integrity) is an unnecessary use of force, particularly given that necessity is generally evaluated in terms of whether force is a ‘last resort’.212 Such uses of force amount to the substitution (and imposition) of the victim state’s views on how to respond to terrorist threats emanating from the host state’s territory for those of the host state. To the extent that the victim state believes that further action should be taken by the host state to respond to the terrorist threat, the issue should be dealt with through co-operative arrangements with the host state.213 This does not suggest that victim states must consult with unfriendly states that they know will not (or cannot) act to counter terrorist attacks launched from their territory before they react in self-defence. But states that have proven themselves co-operative in counter-terrorism should not be subject to violations of their territorial integrity.

Where, however, a host state is unwilling (or, in some cases, unable)214 to prevent its territory from being used as a base of terrorist operations, the victim state is left with little choice. Either it respects the host state’s territorial integrity at great risk to its own security, or it violates that state’s territorial integrity in a limited and targeted fashion, using force against (and only against) the very source of the (p.60) terrorist attack.215 Based on the post-9/11 state practice examined above, the right to use force in foreign territory in response to terrorist attacks that are not attributable to a state, where such force is necessary due to the host state’s complicity or acquiescence in the terrorist activities emanating from its territory, is recognized as meeting the requirements of Article 51 of the UN Charter. The right to target the state itself in response to terrorist attacks that are not attributable to it (given that state’s acquiescence in terrorist activities emanating from its territory) asserted during Operation Enduring Freedom is not supported by this post-9/11 state practice. As Operation Enduring Freedom remains the only example of such a broad right of self-defence, it should certainly not be considered to have expanded the rules of attribution to include complicity or acquiescence in terrorism, whether for the purposes of defining an ‘armed attack’ or for the purposes of state responsibility. The rules of attribution applicable to terrorist attacks therefore remain limited to cases in which non-state actors are de facto organs or de facto agents of the host state in whose territory defensive force is used.

If the standard of attribution is lowered to include complicity or acquiescence in terrorism in the jus ad bellum context, uses of terrorist force could be attributed to complicit or acquiescing states, thereby justifying the use of defensive force directly against those states. The real difficulty with such uses of force (and attempts to justify them) is that targeting a terrorist-harbouring state directly is likely to decrease its counter-terrorism capacity, including its military capacity to effectively assert control over relevant parts of its territory. As a result, where a state’s counter-terrorism failures are limited to a failure to prevent (or acquiescence in) terrorism, targeting the territorial state itself will very rarely, if ever, pass the necessity and proportionality thresholds of the jus ad bellum. One might therefore legitimately wonder if all the proponents of complicity as a basis of attribution achieve is a more coherent legal explanation of the international community’s response to the terrorist attacks of 9/11. Based on the international community’s negative reaction to Israel’s use of force against both Hezbollah and Lebanese infrastructure in the summer of 2006, in response to terrorist attacks by Hezbollah, it is certainly premature to reconceptualize the rules of attribution to legally justify (and explain) the 9/11 related use of force against a terrorist-harbouring state.

It is equally untenable to reconceptualize the rules of attribution for the purposes of state responsibility. Not only is such a reconceptualization not supported by the (p.61) state practice discussed above (were any proposed lowering of the standard of attribution for the purposes of the jus ad bellum carried through to the state responsibility context), there is absolutely no reason at all to label complicity a basis of attribution for the purposes of state responsibility. While there was a driving force (albeit a misguided one) behind reading down the rules of attribution in the jus ad bellum context—to legally account for and authorize uses of defensive force against terrorist-harbouring states—such a reading down in the state responsibility context does nothing but collapse a primary rule into a secondary rule of state responsibility. States are under customary international law and treaty obligations to refrain from supporting terrorist activities216 and to prevent such activities within their territories.217 Complicity in terrorist activities, whether put in evidence through support for or a deliberate failure to prevent terrorism, is in breach of an independent obligation under both customary international law and treaty law. An argument that states should be held directly responsible for positive conduct (the commission of a terrorist act) on the basis of attributability, when all they may be responsible for is an omission (a however deliberate failure to prevent), would render many of the primary rules in the terrorism context redundant.218 While a wrongdoing state’s responsibility is not invoked as often as it might be in the terrorism context, as discussed further in Chapters 4, 5 and 6, holding states responsible as a matter of law for more than they are responsible for as a matter of fact will certainly not encourage more reliance on the regime of state responsibility as a mechanism for re-establishing the primary legal relationship between injured and wrongdoing states.

2.3 Conclusion

A state’s ‘direct’ responsibility for an act of terrorism (as distinguished from responsibility for supporting or failing to prevent acts of terrorism, or for failing to extradite or submit terrorist actors to prosecution) turns on the application of the secondary rules of attribution. But it will be difficult to establish a state’s ‘direct’ responsibility for acts of international terrorism. Part of the reason for this stems from conceptual difficulties in situating terrorism within a legitimate sphere of state activity and qualifying terrorism as falling within the official capacity of state organs. This particular issue, however, is a consequence of the often clandestine nature of terrorism and the evidentiary difficulties that that raises, rather than a consequence of the rules of attribution themselves.

A further difficulty in attributing terrorist conduct to a state is the result of the standard of control set by the ICJ in its application of Article 8 of the ILC Articles on State Responsibility. In particular, the ‘effective control’ standard responds to concerns in the context of military and paramilitary operations, but fails to consider (p.62) the appropriate standard of control in cases where the breach of international law is inherent in the use of force—as in the terrorism context. A flexible and context-sensitive approach to the application of Article 8 of the ILC Articles on State Responsibility, which incorporates the ‘overall control’ standard set out in the ICTY’s Tadić decision, is all that is required to respond to this difficulty. It is rather extreme to propose a complicity-based rule of attribution, or to suggest that attribution should not be the basis of ‘direct’ state responsibility at all, to respond to a problem that is more than amply addressed through flexibility and a sensitive appreciation of different contexts. Complicity-based rules of attribution are equally unnecessary in the jus ad bellum context given the alternative framework available (discussed in Section 2.2.3) for addressing the security concerns of victim states.

Even in the absence of attributability (assuming a sensitive application of the rules), a state’s support for terrorism may still amount to a prohibited use of force or an illegal intervention in the affairs of another state. But state responsibility for participation in terrorist activities is rarely invoked formally, whether such responsibility is characterized as ‘direct’ or ‘indirect’. The increasing use of the ICJ in the use of force context,219 and the potential basis of the Court’s jurisdiction under the TSCs for a state’s sponsorship of or support for acts of international terrorism (discussed in Section 4.2 below), may well stimulate change in this regard.

Notes:

(1) UNSG Report, In larger freedom: towards development, security and human rights for all, UN Doc. A/59/2005 (2005), para 91. See also Report of the High Level Panel on Threats, Challenges and Change, A more secure world: our shared responsibility, UN Doc. A/59/565 (2004), para 160; Saul (2006), 195.

(2) See Section 1.3.

(3) Murphy (1989), 33–4; Murphy et al. (1991), 19.

(4) Ibid.

(5) What amounts to an act of terrorism was not discussed during the negotiations of either the UN Definition of Aggression, UNGA Resolution 3314 (1974), Annex, or the UN Declaration on Friendly Relations, UNGA Resolution 2625 (1970). Instead, terrorism was generally used as a term referencing indirect uses of force by states. Infra notes 9 and 32 and accompanying text.

(6) See also the GA Resolution on the Inadmissibility of State Terrorism, UNGA Resolution 39/159 (1984), which characterizes state terrorism as a violation of Article 2(4) of the UN Charter and the principle of non-intervention.

(7) Higgins (1997), 13–14. See also Murphy et al. (1991), 29; Beres (1995), 239; Saul (2006), 195.

(8) See Section 1.3.

(9) See Report of the Special Committee on the Question of Defining Aggression, UN Doc. A/8019 (1970), paras 26–30.

(10) Ibid, para 127.

(11) See Report of the Special Committee on the Question of Defining Aggression, UN Doc. A/8719 (1972), Appendix B, Section A.

(12) See Report of the Special Committee on the Question of Defining Aggression, UN Doc. A/8019 (1970), para IV.B (7).

(13) See Reports of the Special Committee on the Question of Defining Aggression, UN Doc. A/7620 (1969), paras 26–9, 62, and 69–72; UN Doc. A/8019 (1970), Annex I, para 7; UN Doc. A/8419 (1971), paras 27–8; UN Doc. A/8719 (1972), Section C. But see Bowett (1958), 256–60, correctly arguing that the identification of the concepts of aggression and armed attack should be rejected, because aggression is defined for the purposes of triggering the United Nations’ collective security apparatus, whereas an armed attack triggers a state’s right to use force in self-defence unilaterally.

(14) See Report of the Special Committee on the Question of Defining Aggression, UN Doc. A/7620 (1969), para 127.

(15) Ibid, para 128. See also Ferencz (1973), 419–21, for a summary of the debate. Note that at the time of negotiation, ‘armed attack’ under Article 51 of the UN Charter was generally understood to be restricted to armed attacks that are attributable to states. The concern of Western states might have been alleviated had ‘armed attack’ equally been understood as an attack by non-state actors giving rise to a right to use force in self-defence in cases where the territorial state could not be relied on to prevent its territory from being used as a base of terrorist operations, as argued in Section 2.2.3.

(16) See Report of the Special Committee on the Question of Defining Aggression, UN Doc. A/9019 (1973), Appendix A.

(17) Emphasis added. Art. 1, UN Definition of Aggression, UNGA Resolution 3314 (1974), Annex. See also Stone (1977), 232.

(18) Art. 3(g), UN Definition of Aggression, UNGA Resolution 3314 (1974), Annex.

(19) ‘Sending by or on behalf of a State’ is not a basis of attribution specifically set forth in the ILC Articles on State Responsibility, and therefore can be regarded as a lex specialis basis of attribution, although it closely tracks the attribution threshold set forth in Article 8 of the ILC Articles. Infra note 21.

(20) Emphasis added. Art. 1, UN Definition of Aggression, UNGA Resolution 3314 (1974), Annex. See the ICJ’s treatment of Article 3(g) in its Nicaragua (Nicaragua v. US) and Armed Activities on the Territory of the Congo (DRC v. Uganda) decisions, infra notes 142 and 148 and accompanying text. But see Becker (2006), 179–80, arguing that the ‘sending by or on behalf of a State of armed bands’ threshold in Article 3(g) is not a standard for attributing the conduct of those armed bands to the state, but is rather the act of aggression itself. This argument ignores the fact that Article 1 of the Definition of Aggression defines aggression as a use of armed force by a state. ‘Sending armed bands’ is not in itself a use of armed force, and it must therefore be that the use of armed force by the armed bands, attributable to the state on the basis of the act of sending, is what satisfies the elements of Article 1 coupled with Article 3(g) of the Definition of Aggression.

(21) See e.g. Franck (2002), 65. But see Zanardi (1986), 112, arguing that ‘sending’ implies that the armed bands act as de facto organs of the sending state. Zanardi’s view on Article 3(g) as a standard of attribution is consistent with the travaux préparatoires for the UN Definition of Aggression (see Report of the Special Committee on the Question of Defining Aggression, UN Doc. A/9019 (1973)), but these do not necessarily support attribution on the basis of the de facto organ status of the armed bands, which standard of attribution requires a high level of dependence on the state sending them. See infra note 90 and accompanying text. Article 3(g) as a standard of attribution accords more closely with the ‘acting on instructions of [the state]’ standard set forth in Article 8 of the ILC Articles on State Responsibility, as discussed in Section 2.2.2.

(22) See Report of the Special Committee on the Question of Defining Aggression, UN Doc. A/9019 (1973).

(23) See Lillich and Paxman (1977), 273; Daudet (1997), 203–4. But see the dissenting opinions in Nicaragua, which considered a state’s substantial involvement in the sending of armed bands to amount to an act of aggression by that state. Nicaragua (Nicaragua v. US), Merits, Dissenting Opinion of Judge Schwebel, paras 162–71; Nicaragua (Nicaragua v. US), Merits, Dissenting Opinion of Judge Jennings, 543.

(24) The prohibition of sending armed bands to carry out acts of armed force amounting to aggression has been determined to reflect customary international law. Nicaragua (Nicaragua v. US), Merits, para 195.

(25) National Commission on Terrorist Attacks Upon the United States, 1–14.

(26) In claiming responsibility for the 9/11 terrorist attacks, Bin Laden reportedly threatened new attacks if the policies of the US Government did not change. CBC, ‘Bin Laden claims responsibility for 9/11’, 29 October 2004, 〈http://www.cbc.ca/world/story/2004/10/29/binladen_message041029.html〉.

(27) For instance the attacks could be likened to bombardment by the armed forces of a state against the territory of another state, defined as an act of aggression in Article 3(b), UN Definition of Aggression.

(28) Art. 3(g), UN Definition of Aggression, UNGA Resolution 3314 (1974), Annex. But see Gaeta(2007), 637.

(29) Preamble, UN Declaration on Friendly Relations, UNGA Resolution 2625 (1970).

(30) Article 2(4) of the UN Charter reads that states ‘shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the purposes of the United Nations’.

(31) Nicaragua (Nicaragua v. US), Merits, para 191. See also Armed Activities on the Territory of the Congo (DRC v. Uganda), Judgment, para 162, in which the ICJ holds that the prohibition of state terrorism set forth in the UN Declaration on Friendly Relations, UNGA Resolution 2625 (1970), is also customary international law.

(32) 1st Principle, UN Declaration on Friendly Relations, UNGA Resolution 2625 (1970). See further UN Declaration on International Terrorism, UNGA Resolution 49/60 (1994), para 4; Supplement to the UN Declaration on International Terrorism, UNGA Resolution 51/210 (1996), Annex, para 5; World Summit Outcome Document, UN Doc. UNGA Resolution 60/1 (2005), para 86, all reiterating the prohibition on state terrorism (without defining terrorism) through the prism of the UN Charter and the prohibition on the use of force.

(33) See Sections 2.2.1 and 6.2.4 for full details of the Rainbow Warrior incident.

(34) See Section 2.2.2.

(35) Nicaragua (Nicaragua v. US), Merits, para 228.

(36) 1st Principle, UN Declaration on Friendly Relations, UNGA Resolution 2625 (1970).

(37) See further infra note 49 and accompanying text.

(38) See Armed Activities on the Territory of the Congo (DRC v. Uganda), Judgment, paras 161–5.

(39) Supra note 32 and accompanying text. That acquiescence amounts to a prohibited use of force pursuant to the UN Declaration on Friendly Relations, UNGA Resolution 2625 (1970) further calls into question the distinction the ICJ draws between military and financial support in its Nicaragua decision. If passive support for terrorist conduct amounts to a prohibited use of force, active support for such conduct, whether financial or military in nature, should equally amount to a prohibited use of force.

(40) 3rd Principle, UN Declaration on Friendly Relations, UNGA Resolution 2625 (1970).

(41) See generally Report of the 1966 Special Committee on Principles of International Law Concerning Friendly Relations and Co-operation among States, UN Doc. A/6230 (1966).

(42) Nicaragua (Nicaragua v. US), Merits, para 202.

(43) 3rd Principle, UN Declaration on Friendly Relations, UNGA Resolution 2625 (1970).

(45) Nicaragua (Nicaragua v. US), Merits, para 205.

(46) Ibid. The ICJ considered that, when one state, with a view to the coercion of another state, supports and assists armed bands whose purpose is to overthrow that other state’s government, it is illegally intervening in the internal affairs of the other, whether or not the political objective of the state giving such support is as far reaching as that of the armed band. Nicaragua (Nicaragua v. US), Merits, para 241.

(47) Conforti (1991), 467. Consider also the UN Declaration on the Inadmissibility of Intervention in the Domestic Affairs of States, UNGA Resolution 2131 (1965), para 1: ‘No State has the right to intervene, directly or indirectly, for any reason whatever, in the internal or external affairs of any other State. Consequently, armed intervention and all other forms of interference or attempted threats against the personality of the State or against its political, economic and cultural elements, are condemned’. Emphasis added. In Nicaragua ( Nicaragua v. US), Merits, para 202, the ICJ considered the principle of non-intervention to be a corollary of the principle of sovereign equality of states, and equated the principle to that requiring respect for territorial sovereignty and political integrity.

(48) Nicaragua (Nicaragua v. US), Merits, para 205.

(49) Ibid, para 228. It might be argued that the distinction drawn by the ICJ between military and other types of support is based in part on the fact that financing terrorist activities is prohibited as an instantiation of the principle of non-intervention, but is not listed as prohibited conduct vis à vis terrorist activities under the prohibition of the use of force. 1st Principle and 3rd Principle, UN Declaration on Friendly Relations, UNGA Resolution 2625 (1970). There is no evidence in the travaux préparatoires, however, to suggest that a deliberate distinction was being drawn.

(50) Supra notes 32 and 43.

(51) Murphy et al. (1991), 18. In its Nicaragua decision, the ICJ required a measure of intentionality on the part of the supporting state in order that support for non-state actors amount to intervention. The ICJ attributed the interventionist aims of the contras to the US on the basis of US awareness of those aims. Nicaragua (Nicaragua v. US), Merits, para 205.

(52) The requirement of reasonable notice can be inferred generally from principles of due diligence discussed in Section 3.1.1, and from the Terrorism Financing Convention (in so far as it may be deemed to apply directly to state financing of terrorism, on which see Section 4.2), which only holds a person criminally responsible for financing terrorism if he or she intended that the funds be used, or acted in the knowledge that they were to be used, to finance terrorist acts. Art. 2(1), Terrorism Financing Convention.

(53) Knowledge need not always be proven directly, but in some contexts can be inferred from the circumstances. See for instance the ICJ’s analysis of Serbian knowledge of the serious risk of genocide being perpetrated in Srebrenica. Bosnia Genocide Case, Judgment, paras 436–7.

(54) See Nicaragua (Nicaragua v. US), Merits, paras 242–3, holding that humanitarian assistance to armed groups cannot be regarded as unlawful intervention or in any other way contrary to international law, subject to the proviso that such assistance is strictly for the purposes of alleviating human suffering and to protect life and health, and is given without discrimination.

(55) Supra notes 35–6 and accompanying text.

(56) See Nicaragua (Nicaragua v. US), Merits, para 241. See also Bosnia Genocide Case, Judgment, para 421.

(57) But see Condorelli (1989), 245, arguing that, where the terrorist act is not attributable to the state, support therefor does not amount to an act of direct or indirect aggression, or to a violation of the prohibition on the use of force, but can only amount to a grave intervention in the internal affairs of another state.

(58) In the absence of attributability, state support for a terrorist act still amounts to a breach of that state’s international obligations, but the state is not ‘directly’ responsible for the terrorist conduct. See Fox (2002), arguing that ‘direct’ and ‘indirect’ responsibility serve to indicate the degree of participation of a state in the wrongful act.

(59) See German Settlers Advisory Opinion, 22.

(60) Commentary to Part One, Chapter II, ILC Articles on State Responsibility, para 1.

(61) Art. 4(1), ILC Articles on State Responsibility.

(62) See e.g. League of Nations, Conference for the Codification of International Law, Bases of Discussion for the Conference Drawn up by the Preparatory Committee, Vol. III (Responsibility of States for Damage Caused in their Territory to the Person or Property of Foreigners), LN Doc. C.75.M.69.1929.V, 75; League of Nations, Acts of the Conference for the Codification of International Law Held at The Hague from 13 March to 12 April 1930, Vol. IV (Minutes of the Third Committee), LN Doc. C.351(c) M.145(c).1930.V, 237; Ago (1972), 75–92, paras 11–52; Report of the International Law Commission on the work of its twenty-fifth session, UN Doc. A/9010/Rev.1 (1973), 191–3; Brownlie (1983), 145.

(63) Commentary to Art. 7, ILC Articles on State Responsibility, para 3.

(64) League of Nations, Acts of the Conference for the Codification of International Law Held at The Hague from 13 March to 12 April 1930, Vol. IV (Minutes of the Third Committee), LN Doc. C.351(c) M.145(c).1930.V, 237.

(65) Petrolane v. Iran (Iran–US Claims Tribunal, 1991), 92.

(66) Commentary to Art. 4, ILC Articles on State Responsibility, para 13; Commentary to Art. 7, ILC Articles on State Responsibility, para 7.

(67) Ago (1972), 93, para 56; Crawford (1998a), 29–31, paras 238–43.

(68) See e.g. Youmans Case (US–Mexico General Claims Commission, 1926), 115–16; Caire Case (France–Mexico Mixed Claims Commission, 1929), 531; Velásquez-Rodríguez Case (Inter-American Court of Human Rights, 1988), para 170.

(69) See Communiqué from the French Prime Minister dated 22 September 1985, 74 International Law Reports 261; UNSG Rainbow Warrior Ruling (1986); R. v. Mafart and Prieur, New Zealand (High Court, 22 November 1985), 74 International Law Reports 243, 250.

(70) See Letter from the President of France to the Prime Minister of New Zealand, 8 August 1985, 74 International Law Reports 262.

(72) Ibid.

(73) See Communiqué from the French Prime Minister dated 22 September 1985, 74 International Law Reports 261.

(74) See UNSG Rainbow Warrior Ruling (1986); Apollis (1987). See also Section 3.2.2 below for a discussion of the Ruling in reference to issues of immunity ratione materiae from domestic criminal proceedings.

(75) See Byman (2005), Chapter 2; Hoffman (2006), 27.

(76) Art. 8, ILC Articles on State Responsibility.

(77) Art. 8(a) and Commentary, Report of the International Law Commission on the work of its twenty-sixth session, UN Doc. A/9610/Rev.1 (1974), 283, para 1 and 285, para 8. There is, however, some ambiguity in the Commentaries as to whether acting in concert with or at the instigation of a state might also form the basis for attributing non-state conduct to a state (both of which seem lower standards than acting on instructions of). Ibid, 284, para 5. See also Crawford (1998a), para 200; Kress (2001), 102.

(78) The ICJ held that the conduct of the revolutionaries ‘might be considered as itself directly imputable to the Iranian State only if it were established that, in fact, on the occasion in question the militants acted on behalf on the State, having been charged by some competent organ of the Iranian State to carry out a specific operation’. Emphasis added. Tehran Hostages (US v. Iran), Judgment, para 58. Having concluded that the revolutionaries were not acting on the instructions of the Iranian State, the ICJ then considered a state’s post facto adoption of private conduct as a basis for attributing that conduct to the adopting state. Tehran Hostages (US v. Iran), Judgment, para 74.

(79) Commentary to Art. 8, ILC Articles on State Responsibility, para 2.

(80) Emphasis added. Ibid.

(81) Bosnia Genocide Case, Judgment, para 400. The ICJ’s decision was in application of Article 8 of the ILC Articles on State Responsibility, and therefore did not say anything about the lex specialis rule of attribution under Article 3(g) of the UN Definition of Aggression, UNGA Resolution 3314 (1974), Annex.

(82) See Commentary to Art. 7, ILC Articles on State Responsibility, para 3, citing the Italian position that there is ‘no practical way of proving that [an] agent had or had not acted on orders received’ in support of the rule that the state should be responsible for all conduct of its organs, even if ultra vires.

(83) Nicaragua (Nicaragua v. US), Merits, paras 94 and 108. One commentator has argued that the ICJ’s decision on attribution may well have been different if the US had created the contras. See de Hoogh (2001), 269.

(84) Nicaragua (Nicaragua v. US), Merits, paras 100 and 108.

(85) Ibid, para 100.

(86) Ibid, para 106.

(87) Ibid, paras 101–2.

(88) Ibid, para 106. The ICJ did not consider it to have been established that ‘all the operations launched by the contra force, at every stage of the conflict, reflect strategy and tactics wholly devised by the United States’. Ibid.

(89) Ibid, paras 112 and 115.

(90) Nicaragua (Nicaragua v. US), Merits, para 109. In its Bosnia Genocide Case decision, the ICJ characterized this test as determinative of de facto organ status, and conduct carried out by de facto organs would be attributable to a state on the basis of Article 4 of the ILC Articles on State Responsibility. Bosnia Genocide Case, Judgment, paras 390–1 and 397. But see Griebel and Plücken (2008), 612–13, arguing that the dependence test set forth in the Nicaragua decision should not be characterized as a de facto organ test. For a vigorous critique of Griebel and Plücken’s argument, see Milanovic (2009).

(91) Nicaragua (Nicaragua v. US), Merits, Memorial of Nicaragua, paras 37–59.

(92) Ibid, paras 255–62.

(93) Nicaragua (Nicaragua v. US), Merits, para 228. But see Tadić (ICTY-94-1-A), Separate Opinion of Judge Shahabuddeen, paras 8–12.

(94) The ICJ did address specific military operations (i.e. an attack on Sandino International Airport on 8 September 1983 and an attack on oil storage facilities at Benjamin Zeledon on 2 October 1983) when considering the attributability of certain non-state conduct (carried out by the so-called Unilaterally Controlled Latino Assets) because the specifics of US involvement in those operations was addressed in the pleadings. See Nicaragua (Nicaragua v. US), Merits, para 81.

(95) Ibid, para 115.

(96) Ibid.

(97) Emphasis added. Ibid.

(98) Tadić (ICTY-94-1-T); Tadić (ICTY-94-1-A).

(99) Tadić (ICTY-94-1-T), paras 592–604.

(100) Tadić (ICTY-94-1-A), Prosecution Brief, paras 2.21–2.23.

(101) Tadić (ICTY-94-1-A), para 98.

(102) Tadić (ICTY-94-1-A), para 137. The Appeals Chamber subsequently reaffirmed its Tadić ‘overall control’ test, holding that ‘[t]he “overall control” test could thus be fulfilled even if the armed forces acting on behalf of the “controlling State” had autonomous choices of means and tactics although participating in a common strategy along with the “controlling State” ’. Delalić et al. (ICTY-96-21-A), para 47.

(103) See Commentary to Art. 8, ILC Articles on State Responsibility, para 5; Bosnia Genocide Case, Judgment, para 404.

(104) Crawford (1998a), 4; Art. 8, ILC Articles on State Responsibility.

(105) Commentary to Art. 8, ILC Articles on State Responsibility, para 4.

(106) Ibid, para 5.

(107) Bosnia Genocide Case, Judgment, paras 403–4.

(108) Ibid, para 406. But see Bosnia Genocide Case, Judgment, Dissenting Opinion of Vice-President Al-Khasawneh, para 39.

(109) Bosnia Genocide Case, Judgment, para 399.

(110) Ibid, para 400.

(111) See e.g. Condorelli (1989); Reisman (1999), 39; Dinstein (2005), 182–3; Slaughter and Burke-White (2002), 20; Chase (2004), Becker (2006). For general remarks on whether ‘effective control’ remains the only standard of control, see Kress (2001); Griebel and Plücken (2008), 618–20. See also Brownlie (2008), 419, suggesting that attribution may take different forms, depending upon the primary rule applied.

(112) ILC, Comments and Observations received from Governments on State Responsibility, UN Doc. A/CN.4/515 (2001), 23. See also Blaškić (ICTY-95-14-T), Declaration of Judge Shahabuddeen, arguing that any control over non-state actors, for the purposes of attribution, needs to be effective—and what threshold of control amounts to effective control will depend on the circumstances.

(113) Report of the International Law Commission on the work of its fiftieth session, UN Doc. A/53/10 and Corr.1 (1998), para 395. See also Dupuy (2004), 10, arguing that the ambiguity in Article 8 was likely deliberate, in order to leave some flexibility for different possible interpretations. But see Bosnia Genocide Case, Judgment, para 401: ‘[t]he rules for attributing alleged internationally wrongful conduct to a State do not vary with the nature of the wrongful act in question in the absence of a clearly expressed lex specialis’.

(114) See Bayindir v. Pakistan (ICSID, 2009), para 130: ‘Finally, the Tribunal is aware that the levels of control required for a finding of attribution under Article 8 in other factual contexts, such as foreign armed intervention or international criminal responsibility, may be different. It believes, however, that the approach developed in such areas of international law is not always adapted to the realities of international economic law and that they should not prevent a finding of attribution if the specific facts of an investment dispute so warrant’.

(115) Non-military support raises more complicated issues because several organizations designated by the West as ‘terrorist’ equally carry out governance functions in the regions within which they operate, for instance Hamas in Gaza and Hezbollah in Lebanon. As a result, financial and other forms of non-military assistance may well be intended for the purposes of assisting the organization in carrying out its governance-related responsibilities.

(116) Crawford (1998a), 23, para 216.

(117) Regarding the unsuitability of the ‘effective control’ test for the attribution of genocide, see Bosnia Genocide Case, Judgment, Dissenting Opinion of Vice-President Al-Khasawneh, para 39.

(118) Byman (2005), 54–66.

(119) Byman (2005), 54.

(120) See Commentary to Part One, Chapter II, ILC Articles on State Responsibility, para 9.

(121) See Chapter 3 on the obligations to prevent and extradite or submit to prosecution.

(122) See Ago (1972), 71, para 65.

(123) See e.g. Cotesworth and Powell Case (Great Britain/Colombia), 2082; Poglioli Case (Italy/Venezuela), 689; Eagleton (1928), 77; Starke (1938), 367–9. See also de Frouville (2010), tracing the movement away from complicity as a basis of attribution from Grotius to the present day ILC Articles on State Responsibility.

(124) For a critique of the artificiality of the link, see Christenson (1983), 322.

(125) The US–Mexico Claims Commission’s decision in the Janes Case (1926), paras 114–15, was the first clear rejection of complicity as a basis of direct state responsibility for underlying criminal conduct, at least in relation to a failure to punish. See also British Property in Spanish Zone of Morocco Case (UK/Spain), 641–2. Even though codification efforts did not unambiguously distinguish between state responsibility based on the negligent failure to prevent private conduct where there was an international obligation to do so and responsibility based on the attributability of the unprevented private conduct (see e.g. Institute of International Law (1927), 229; American Institute of International Law (1929), 232; Harvard Law School (1929), 187–9; League of Nations, Conference for the Codification of International Law, Bases of Discussion for the Conference drawn up by the Preparatory Committee, Vol. III (Responsibility of States for Damage caused in their Territory to the Person or Property of Foreigners), LN Doc. C.75.M.69.1929.V, 515–18, 534), scholarly opinion was more in line with the Janes Case distinction between direct and indirect responsibility. See Borchard (1915), 217; Brierly (1928); Rice (1934), 249.

(126) See Ago (1972), 119–20, para 135. See also Bosnia Genocide Case, Judgment, para 420, in which the ICJ considered state responsibility for complicity in genocide, an ancillary offence under the Genocide Convention, and clearly distinguished it from a standard of attribution. But see Sohn and Baxter (1974), 235. See infra Chapter 4, notes 67–72 and accompanying text for a discussion of state responsibility for accessory crimes (like accomplice liability) defined in the TSCs.

(127) Art. 51, UN Charter.

(128) See Brownlie (1963). But see Bowett (1958) and Schwebel (1972), arguing that the ‘inherent’ nature of the right of self-defence recognized in the Charter preserves earlier customary law, including anticipatory self-defence. On the debate, see Gray (2008), 117–19.

(129) See e.g. Cassese (1989), 596–7 (requiring attributability under the law of state responsibility, but, in line with the dissents in Nicaragua (Nicaragua v. US), Merits, describing state support and acquiescence in terrorism as a ‘grey’ area in the law that might form the basis of attribution); Zanardi (1986); Condorelli (2001), 838; Corten (2002), 55. But see Palestinian Wall Advisory Opinion, Separate Opinion of Judge Higgins, para 33 (questioning the ICJ’s conclusion in Nicaragua, given that there is nothing in the language of the Charter itself that restricts ‘armed attacks’ to uses of force by a state); Palestinian Wall Advisory Opinion, Separate Opinion of Judge Kooijmans, para 35; Armed Activities on the Territory of the Congo (DRC Uganda), Judgment, Separate Opinion of Judge Kooijmans, para 28; Wedgwood (1999), 564; Franck (2000), 840; Murphy (2002), 50; Paust (2002), 534; Greenwood (2003), 419–21; Stahn (2003), 42.

(130) The terrorist attack committed by the non-state actors must also be of sufficient gravity to amount to an armed attack within the meaning of Article 51 of the UN Charter. See Nicaragua (Nicaragua v. US), Merits, para 195; Oil Platforms (Iran v. US), Judgment, para 51.

(131) See Randelzohfer (2002), 801; Jinks (2003); Jinks (2003a); Brunnée and Toope (2004), 795; Janse (2006), 168–9; Tams (2009), 385. But see Trapp (2009).

(132) See Sassòli (2001), 223; Paust (2002), 540–3; Guillaume (2004), 545–7.

(133) See Simpson (2004), 335.

(134) See Becker (2006), suggesting that the attribution-based approach to state responsibility (which he refers to as the ‘agency paradigm’) needs to be reconceptualized in order to respond properly to (among other things) the realities of state practice under Article 51 of the UN Charter. See Trapp (2006) for a critique of this argument. See also discussion in Tams (2009); Trapp (2009); and Tams (2009a).

(135) See e.g. Armed Activities on the Territory of the Congo (DRC v. Uganda), Judgment, Separate Opinion of Judge Simma, para 8; Separate Opinion of Judge Kooijmans, para 25.

(136) The ICJ held that the US was responsible for financing, training, and providing logistical support to the contras (including the supply of intelligence as to Nicaraguan troop movements). Supra notes 83–9 and accompanying text.

(137) The ICJ held that Nicaragua was not in fact responsible for the arms traffic, to the extent such arms traffic existed. Nicaragua (Nicaragua v. US), Merits, paras 154–5.

(138) Nicaragua (Nicaragua v. US), Merits, para 113. See Section 2.2.2 for a discussion of the ICJ’s decision on the attributability of humanitarian law violations committed by the contras during the course of their paramilitary operations to the US.

(139) Nicaragua (Nicaragua v. US), Merits, para 105.

(140) Ibid, para 156. The ICJ’s argument is effectively a commentary on the necessity of the US operation. See Sohn (1989), 874.

(141) Scholars writing at the time of the decision were divided on the attribution-based definition of ‘armed attack’ advanced by the Court. Arguing that an ‘armed attack’ is limited to uses of force by one state against another, see e.g. Brownlie (1963), 278–9; Zanardi (1986). But see Dinstein (1987), 144–6; Combacau (1986), 26.

(142) Nicaragua (Nicaragua v. US), Merits, para 195. The ICJ applied Article 3(g) of the UN Definition of Aggression, UNGA Resolution 3314 (1974), Annex, as a standard of attribution. See further the Court’s treatment of Article 3(g) as a standard of attribution for the purpose of defining an ‘armed attack’ in its Armed Activities on the Territory of the Congo (DRC v. Uganda) decision, infra note 148 and accompanying text.

(143) Palestinian Wall Advisory Opinion, para 139.

(144) Palestinian Wall Advisory Opinion, para 139. But see Palestinian Wall Advisory Opinion, Separate Opinion of Judge Higgins, para 34; Declaration of Judge Buergenthal, para 6.

(145) See Tams (2005); Murphy (2005). But note that the ICJ’s opinion has been interpreted as at least implicitly recognizing a right to use force in self-defence against non-state terrorist actors in foreign territory, even though refusing to accept such a right as applicable in the circumstances based on the occupied status of the territory from which the terrorist attacks emanated. See Canor (2006), 132.

(146) Armed Activities on the Territory of the Congo (DRC v. Uganda), Judgment, para 146.

(147) Ibid, para 147.

(148) Armed Activities on the Territory of the Congo (DRC v. Uganda), Judgment, para 146. Interestingly, both the DRC and Uganda, in their pleadings, accepted a lesser degree of state involvement than that set out in Nicaragua as a basis for attributing the activities of armed bands to the host state for the purposes of self-defence. In particular, the DRC considered that a state’s support for rebel groups, including by deliberately allowing them access to its territory, could be characterized as an ‘armed attack’ within the meaning of Article 51 of the UN Charter, justifying a unilateral response. Armed Activities on the Territory of the Congo (DRC v. Uganda), Judgment, CR 2005/03 (translation), 12 April 2005, para 21.

(149) Armed Activities on the Territory of the Congo (DRC v. Uganda), Judgment, para 146.

(150) Ibid, paras 118 and 147.

(151) Ibid, paras 81–6.

(152) Commentators are also increasingly arguing in support of a right to use force in self-defence in response to armed attacks by non-state actors. See e.g. Franck (2000), 840; Murphy (2002), 50; Paust (2002), 534; Greenwood (2003), 522; Dinstein (2005), 204–7; Lubell (2010), 35; Moir (2010), 54.

(153) Letter dated 20 August 1998 from the Permanent Representative of the United States of America to the United Nations addressed to the President of the Security Council, UN Doc. S/1998/780.

(154) The Sudan, in a letter to the Security Council, denied that the pharmaceutical plant in Khartoum was used for terrorist purposes. Letter dated 21 August 1998 from the Permanent Representative of The Sudan to the United Nations addressed to the President of the Security Council, UN Doc. S/1998/786. The League of Arab States and Non-Aligned Movement condemned the US for its attack on the Sudan. Letter dated 21 August 1998 from the Chargé D’Affaires a.i. of the Permanent Mission of Kuwait to the United Nations addressed to the President of the Security Council, UN Doc. S/1998/789; Letter dated 24 August 1998 from the Chargé D’Affaires a.i. of the Permanent Mission of Kuwait to the United Nations addressed to the President of the Security Council, UN Doc. S/1998/800; Letter dated 21 September 1998 from the Permanent Representative of the Sudan to the United Nations Addressed to the President of the Security Council, UN Doc. S/1998/879.

(155) The US position at the time was that Al Qaeda operated on its own, without having to depend on a state sponsor for support (although depending on state acquiescence). See Murphy (2000), 367.

(156) But see Franck, effectively arguing that a failure to condemn reflects international acceptance of a particular operation. Franck (2002), 65–6.

(157) Letter dated 7 October 2001 from the Permanent Representative of the United States of America to the United Nations addressed to the President of the Security Council, UN Doc. S/2001/946. While accusing the Taliban of acquiescence, the letter stopped short of alleging that the Taliban was directly responsible for the 9/11 terrorist attacks.

(158) See Gray (2008), 199; Greenwood (2003), 421. But see Cassese (2001), 996.

(159) UNSC Resolution 1368 (2001). The Council again reaffirmed the right to individual and collective self-defence in UNSC Resolution 1373 (2001).

(160) See US Senate, Report of the Committee on Foreign Relations on the North Atlantic Treaty, Executive Report No. 8, 13; Art. 3, Inter-American Treaty of Reciprocal Assistance, 2 September 1947, 21 UNTS 77.

(161) See NATO update, 2 October 2001, 〈http://www.nato.int/docu/update/2001/1001/e1002a.htm〉; Inter-American Treaty of Reciprocal Assistance, 24th Ministers Meeting, 19 September 2001, 〈http://www.oas.org〉.

(162) See Letter dated 9 October 2001 from the Permanent Representative of Belgium to the United Nations addressed to the Secretary-General, UN Doc. S/2001/967; Letter dated 24 October 2001 from the Chargé D’Affaires a.i. of the Permanent Mission of Canada to the United Nations addressed to the President of the Security Council, UN Doc. S/2001/1005; Letter dated 29 November 2001 from the Permanent Representative of Germany to the United Nations addressed to The President of the Security Council, UN Doc. S/2001/1127; Letter dated 17 December 2001 from the Permanent Representative of New Zealand to the United Nations addressed to the Secretary-General, UN Doc. S/2001/1193.

(163) But see Paust (2002), 540–3, arguing that Al Qaeda was a legitimate target of defensive force, but that the Taliban, to which the 9/11 terrorist attacks could not be attributed (because acquiescence is not a basis for attribution), was not a legitimate target.

(164) For an argument to this effect, see Jinks (2003); Jinks (2003a); Janse (2006), 168–9.

(165) See Murphy (2002); Ratner (2002), 913; M.E. O’Connell (2002), 32; Byers (2002); Stahn (2003), 42–9.

(166) Supra notes 157 and 162. See also 9/11 Commission Report, which called into doubt the degree of control the Taliban exercised over Al Qaeda, instead finding that senior officials in the Taliban regime were opposed to the 9/11 terrorist attacks.

(167) UNSC Resolution 1267 (1999); UNSC Resolution 1333 (2000).

(168) See Commentary to Art. 11, ILC Articles on State Responsibility; Tehran Hostages (US v. Iran), Judgment, para 74. See further Rowe (2002), 308; Stahn (2002), 220–1; Moir (2010), 66–8.

(169) SC 4836th meeting (2003), 5.

(170) Ibid.

(171) Letter dated 5 October 2003 from the Permanent Representative of the Syrian Arab Republic to the United Nations addressed to the President of the Security Council, UN Doc. S/2003/939.

(172) Letter dated 5 October 2003 from the Permanent Representative of Lebanon to the United Nations addressed to the President of the Security Council, UN Doc. S/2003/943.

(173) Council Common Position 2005/847/CFSP of 29 November 2005, 2005 Official Journal of the European Union (L 314/41).

(174) SC 4836th meeting (2003), 9 (Spain, UK), 10 (Germany), 11 (France).

(175) See SC 4836th meeting (2003). Only the US, which also characterizes Islamic Jihad as a terrorist organization, did not condemn the Israeli attack, and instead admonished Syria for ‘harbouring and supporting the groups that perpetrate terrorist acts’. Ibid.

(176) UN Doc. SG/SM/8918 (2003).

(177) See Gray (2008), 237.

(178) Released 30 April 2003. See 〈http://www.un.org/News/dh/mideast/roadmap122002.pdf〉.

(179) Israel claimed that it ‘has repeatedly been compelled to act not against Lebanon, but against the forces and the monstrosity which Lebanon has allowed itself to be taken hostage by’. SC 5503rd meeting (2006), 4. Israel also suggested that Lebanon, Iran and Syria were responsible for Hezbollah’s activities, but did not appear to be suggesting attributability for the purposes of a defensive use of force. See SC 5489th meeting (2006), 6.

(180) See BBC, ‘Israel Imposes Lebanon Blockade’, 13 July 2006, 〈http://news.bbc.co.uk/2/hi/middle_east/5175160.stm〉.

(181) See BBC, ‘Q&A: Mid-East War Crimes’, 21 July 2006, 〈http://news.bbc.co.uk/2/hi/middle_east/5198342.stm〉; Human Rights Watch, ‘Israeli Indiscriminate Attacks Killed Most Civilians’, 〈http://www.hrw.org/en/news/2007/09/05/israellebanon-israeli-indiscriminate-attacks-killed-most-civilians〉; Amnesty International, ‘Deliberate destruction or “collateral damage”? Israeli attacks on civilian infrastructure’, 〈http://web.amnesty.org/library/print/ENGMDE180072006〉.

(182) See SC 5489th meeting (2006), 9; SC 5492nd meeting (2006), 3; SC 5493rd meeting (2006), 14; SC 5498th meeting (2006), 6.

(183) See SC 5508th meeting (2006), 5.

(184) SC 5489th meeting (2006), 9–17; SC 5493rd meeting (2006), 17. The Secretary General also acknowledged Israel’s right to defend itself against Hezbollah attacks under Article 51 of the UN Charter. SC 5492nd meeting (2006), 3; SC 5498th meeting (2006), 3.

(185) SC 5489th meeting (2006), 9–17. See also the statement of the Secretary General to the Security Council, SC 5492nd meeting (2006), 4 and UNSC Resolution 1559 (2004), paras 1–3; UNSC Resolution 1583 (2005), paras 3–4; UNSC Resolution 1655 (2006), paras 3, 6 and 8; UNSC Resolution 1680 (2006), preamble; UNSC Resolution 1701 (2006), para 3.

(186) Lebanon expressly acknowledged that it needed to extend its authority throughout its territory. SC 5493rd meeting (2006), 13.

(187) See Section 3.1.2 regarding incapacity to prevent international terrorism as a limitation on state responsibility for such failure. On the use of defensive force against non-state actors in the territory of a state that is incapable of fulfilling its duty of diligent terrorism prevention, see Dinstein (1987), 146. See also Armed Activities on the Territory of the Congo (DRC v. Uganda), Judgment, Separate Opinion of Judge Kooijmans, paras 27–31.

(188) SC 5489th meeting (2006), 9 (Argentina), 12 (Japan), 12 (UK), 13–14 (Tanzania considered Israel’s use of force as disproportionate without having expressly recognized Israel’s right to use force in self-defence), 14 (Peru), 15 (Denmark), 16 (Slovakia), 16 (Greece), 17 (France). The US is the only state to have explicitly recognized Israel’s right to defend itself without characterizing Israel’s defensive measures as disproportionate or excessive. The Secretary General also condemned Israel’s excessive use of force. SC 5492nd meeting (2006), 3; SC 5498th meeting (2006), 3. See further Kirgis (2006).

(189) See e.g. Letter dated 24 July 1995 from the Chargé D’Affaires a.i. of the Permanent Mission of Turkey to the United Nations addressed to the President of the Security Council, UN Doc. S/1995/605; Identical letters dated 27 June 1996 from the Chargé D’Affaires a.i. of the Permanent Mission of Turkey to the United Nations addressed to the Secretary-General and to the President of the Security Council, UN Doc. S/1996/479; Identical letters dated 16 July 1997 from the Chargé D’Affaires a.i. of the Permanent Mission of Turkey to the United Nations addressed to the Secretary-General and to the President of the Security Council, UN Doc. S/1997/552. Turkey notably failed to invoke Article 51 of the UN Charter in its communications with the Security Council, or to clearly characterize its targeted use of force against the PKK as in exercise of the right of self-defence.

(190) Keesing’s, Vol. 40, January 1994, 39834.

(191) Keesing’s, Vol. 41, March 1995, 40473.

(192) Keesing’s, Vol. 43, May 1997, 41651; Keesing’s, Vol. 43, October 1997, 41877.

(193) Identical letters dated 14 June 1997 from the Permanent Representative of Iraq to the United Nations addressed to the Secretary-General and to the President of the Security Council, UN Doc. S/1997/461; Keesing’s, Vol. 41, March 1995, 40474; Keesing’s, Vol. 41, April 1995, 40522. See also Ruys (2005), 295–6. According to Libya, the US did however support Turkish uses of force against the PKK as a legitimate exercise of the right of self-defence. See Letter dated 12 July 1995 from the Chargé D’Affaires a.i. of the Permanent Mission of the Libyan Arab Jamahiriya to the United Nations addressed to the President of the Security Council, UN Doc. S/1995/566.

(194) See Keesing’s, Vol. 52, July 2006, 47377–8; Keesing’s, Vol. 52, July 2006, 47377–8; Keesing’s, Vol. 53, October 2007, 48219.

(195) Keesing’s, Vol. 53, October 2007, 48219.

(196) Keesing’s, Vol. 52, July 2006, 47377–8.

(197) Keesing’s, Vol. 53, December 2007, 48316. Turkish forces had carried out a number of more limited military operations against PKK fighters in the fall of 2007. See Al Jazeera, ‘Turkey “hits PKK targets in Iraq” ’, 24 October 2007, 〈http://english.aljazeera.net/NR/exeres/14FA7823-911C-4456-B8DB-6CD27C4DE07F.htm〉.

(198) BBC, ‘US denies backing Turkey PKK raid’, 17 December 2007, 〈http://news.bbc.co.uk/2/hi/europe/7147375.stm〉.

(199) See e.g. Keesing’s, Vol. 53, June 2007, 48009.

(200) Al Jazeera, ‘Toll rises in Turkey-PKK conflict’, 25 February 2008, 〈http://english.aljazeera.net/NR/exeres/3E14DD15-F2D1-4C65-8148-5200DFB3E975.htm〉.

(201) See BBC, ‘Iraq warns Turkey over incursion’, 23 February 2008, 〈http://news.bbc.co.uk/2/hi/europe/7260478.stm〉.

(202) Ibid.

(204) Keesing’s, Vol. 54, March 2008, 48456.

(205) Keesing’s, Vol. 54, March 2008, 48456.

(206) Ibid.

(207) OAS, Convocation of the Meeting of Consultation of Ministers of Foreign Affairs and Appointment of a Commission, 5 March 2008, CP/RES. 930 (1632/08).

(208) Speech of Colombian Ambassador to OAS, 4 March 2008, 〈http://www.oas.org/speeches/speech.asp?sCodigo=08-0021〉.

(209) See BBC, ‘Ecuador seeks to censure Colombia’, 5 March 2008, 〈http://news.bbc.co.uk/2/hi/americas/7278484.stm〉.

(210) See also claims by the Russian Federation that, despite Georgian assurances that it was restoring order along its border with Russia, Georgia was in fact unwilling to take measures to halt terrorist attacks against Russian territory from its border region. On the basis of Georgia’s failure to address terrorism emanating from its territory, Russia asserted a right to use force directly against non-state actors in Georgian territory. Letter dated 31 July 2002 from the Chargé D’Affaires a.i. of the Permanent Mission of the Russian Federation to the United Nations addressed to the Secretary-General, UN Doc. S/2002/854; Letter dated 11 September 2002 from the Permanent Representative of the Russian Federation to the United Nations addressed to the Secretary-General, UN Doc. S/2002/1012. Georgia claimed that Russia’s characterization of the facts was inaccurate. Letter dated 13 September 2002 from the Permanent Representative of Georgia to the United Nations addressed to the Secretary-General, UN Doc. S/2002/1035; Identical letters dated 15 September 2002 from the Permanent Representative of Georgia to the United Nations addressed to the Secretary-General and the President of the Security Council, UN Doc. A/57/408–S/2002/1033 (2002).

(211) See Cassese (2001), 997; Beard (2002), 580–2.

(212) See Green (2009), 79, evaluating the state practice and concluding that ‘the interpretation of the necessity criterion as requiring that forcible action in self-defence may be taken only as a “last resort” is correct’. See also Ago (1980), para 120; Gardam (2004), 152–3. But see Schachter (1991), 152.

(213) For instance, US raids against militants in Pakistan have been condemned by Pakistan as an intrusion on its sovereignty. Pakistan further contends that such raids threaten to hurt progress being made against the militants by Pakistani forces, and that any US military operations need to be decided in cooperation with the Pakistani authorities. See Reuters, ‘U.S. raids hurt terrorism fight: Pakistan minister’, 2 October 2008, 〈http://www.reuters.com/article/topNews/idUSTRE4910AA20081002〉. To the extent true, doubts regarding Pakistan’s commitment to the ‘war on terror’ might justify US uses of force in Pakistani territory (targeting and only targeting non-state terrorist actors) as necessary given an inability to rely on the host state to prevent its territory from being used as a base of terrorist operations.

(214) See Section 3.1.3 for a discussion of the rapprochement between the obligation to refrain from acquiescing in, and the obligation to prevent, terrorism.

(215) Trapp (2007), 147. Article 2(4) of the UN Charter prohibits uses of force against the territorial integrity (and political independence) of states. Using force against the base of operations of non-state terrorist actors within another state’s territory surely amounts to a violation of that state’s territorial integrity. As a matter of logic, a use of defensive force pursuant to Article 51 of the UN Charter should only properly qualify as an exception to the prohibition on the use of force if it excuses the violation of territorial integrity (or political independence). When the state in whose territory defensive force is employed is the aggressor or perpetrator of the armed attack (or the armed attack is attributable to it), the excuse for violating that state’s territorial integrity is readily available. Where the conduct is not attributable to the host state, the excuse for the violation of territorial integrity is based on the state’s acquiescence in terrorist activities, which itself amounts to a prohibited use of force under the UN Declaration on Friendly Relations, UNGA Resolution 2625 (1970). See Trapp (2007), 145–6; Trapp (2009).

(216) See Section 2.1.

(217) See Section 3.1.

(218) See further Trapp (2009).

(219) See Gray (2003).