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Complicity in International Law$

Miles Jackson

Print publication date: 2015

Print ISBN-13: 9780198736936

Published to Oxford Scholarship Online: April 2015

DOI: 10.1093/acprof:oso/9780198736936.001.0001

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State Complicity—A Framework

State Complicity—A Framework

(p.125) 6 State Complicity—A Framework
Complicity in International Law

Miles Jackson

Oxford University Press

Abstract and Keywords

This chapter provides an introduction to Part C of the work, which comprises Chapters 6-9 and assesses state complicity in international law, a subject which historically received little attention. Chapter 6 also introduces the divide between state participation in the actions of other states (Chapter 7) and state participation in the actions of non-state actors (Chapters 8 and 9). It shows how the traditional normative structure of international law made it impossible to account for the latter through doctrines of complicity. It also defends the role of complicity as an important concept for understanding states’ obligations in international law.

Keywords:   state complicity, law of neutrality, non-state actors, due diligence obligations

6.1. State Complicity in State Wrongdoing

Historically, international law failed to adequately regulate state complicity in the wrongdoing of other states. In his Hague Lectures of 1939, Ago argued that:

[I]‌t appears inconceivable in international law to have any form of complicity, participation, or incitement to a delict. The law of nations, in its current structure, does not allow for such forms of a consideration shared by several subjects with respect to a single delict; these constructs are characteristic of the nature and development of domestic criminal law.1

One way to understand the traditional absence of a general prohibition on state complicity is within the competing constructs of bilateralism and community interest.2 In this context, bilateralism engenders an understanding of international law defined by correlative rights and obligations owed by subjects to each other.3 The participation of third states—that is to say, the complicity of third states—in the breach of obligations owed by one state to another might be said to be difficult to account for within a bilateralist framework.4 There is something to this view. These difficulties are heightened at the stage of dispute settlement before an international tribunal, where the Monetary Gold principle may limit the admissibility of claims for (p.126) responsibility.5 The non-prohibition of complicity epitomizes what Bruno Simma has called the ‘value-poverty of bilateralist international law’.6 It is insufficient that states concern themselves only with the wrongs they commit themselves.7

But even within a traditional bilateralist framework, ideas of complicity and its kindred forms of responsibility played a role.8 One example is the law of neutrality. Neutrality regulates the relationship between neutral states and belligerents through the core principles of non-participation and non-discrimination.9 The principle of non-participation gives rise to a number of duties that are related to forms of complicity.10 For instance, Article 6 of the Hague Convention concerning the Rights and Duties of Neutral Powers in Naval War provides that ‘[t]‌he supply, in any manner, directly or indirectly, by a neutral Power to a belligerent Power, of war-ships, ammunition, or war material of any kind whatever, is forbidden’.11 Neutrality also prescribes extensive rules on the use of neutral powers’ territory by belligerents.12 The point is not that the breach of the rule of non-participation gives rise to a form of derivative responsibility in respect of a subsequent wrong of the belligerent. Rather, the law of neutrality entails an instance where obligations arise on a third state in respect of their relationship with other states.

The law of neutrality was inevitably affected by the rise of the Charter system of collective security and the prohibition on the use of force in international law.13 Interestingly, the Charter system sets out a rule much closer in rationale to that of a prohibition on complicity. Article 2(5) of the Charter requires that ‘[A]‌ll Members…refrain from giving assistance to any state against which the United Nations is taking preventive or enforcement action’.14 Complicity entails participation in wrongdoing. The decision of the Security Council to take preventive or enforcement action both triggers (p.127) member states’ obligations of non-assistance and, in some instances, entails a (political, at least) determination of wrongful conduct by the aggressor state.15

Leaving aside the law of neutrality and changes brought by the Charter system, Ago’s general point about the traditional absence of complicity rules is accurate. International law traditionally contained no general prohibition on state complicity in the internationally wrongful act of another state—there was no international analogue to common domestic doctrines of accomplice or accessorial liability.16 Short of joint perpetration, as a general rule, participants in another state’s commission of an internationally wrongful act were not implicated by international law’s assignment of responsibility.

6.2. State Participation in the Acts of Non-State Actors— A Conceptual Difficulty

Participating in the wrongful acts of other states is not the only way that states contribute to harmful conduct. Non-state actors commit acts inimical to the rights and interests of both states and individuals. States sometimes participate in those acts. With a sufficient degree of dependence, direction, or control, the conduct of the non-state actor becomes attributable to the state.17 As argued below, the requisite connection between the state and non-state actor for attribution is marked by a search for an agency relationship.18 In the absence of lex specialis, a complicit relationship is insufficient for attribution.

Short of such an agency relationship, the question is whether international law imposes complicity obligations on states in respect of the conduct of non-state actors. Here, there is a conceptual difficulty for complicity. The essential logic of complicity is to tie the accomplice, through its complicit acts, to the wrongdoing committed by another actor.19 Where international law is silent as to the wrongfulness of the acts committed by the other actor, it is difficult to see what wrong the putative accomplice can be complicit in.20 This problem flows from the essential derivative nature of complicity.21

(p.128) This conceptual difficulty is but one implication of the traditional normative structure of the international legal system.22 Historically, international law was addressed to states, and indeed states remain the primary bearers of rights and obligations in international law.23 The absence of regulation of the conduct of non-state actors simply denied the possibility of state complicity in relation to that conduct, for there was no wrong to which the state might be linked by the complicity rule.

This is not to say that international law is silent on state participation—short of attribution—in harms caused by another actor. In a number of areas, international law does impose what might be called obligations of non-participation, as opposed to complicity obligations, in the actions of another actor. For instance, as elements of the principle of the non-use of force, the General Assembly’s Declaration on Friendly Relations, adopted unanimously in 1970, provides:

Every State has the duty to refrain from organizing or encouraging the organization of irregular forces or armed bands, including mercenaries, for incursion into the territory of another State.

Every State has the duty to refrain from organizing, instigating, assisting or participating in acts of civil strife or terrorist acts in another State or acquiescing in organized activities within its territory directed towards the commission of such acts, when the acts referred to in the present paragraph involve a threat or use of force.24

These provisions, which reflect customary international law,25 might be seen as analogous to traditional duties of neutrality. Just as the violation of the duty of neutrality does not give rise to a form of derivative responsibility in relation to some wrongful act of the belligerent state, so the participation by the state does not give rise to derivative responsibility in relation to some wrongful act of the armed band. In both cases, the state’s responsibility for its wrongful participation is not linked to any wrong of a principal actor.26 Instead, a number of classic modes of complicity are used to constitute a direct and independent obligation of non-participation binding the state.27

(p.129) In addition, many instances of state participation in the harms caused by non-state actors are swept up by broader positive obligations imposed on states to protect against harms to other states or individuals.28 The obligation on states to protect against harm is ordinarily conditioned by a due diligence rule, and thus may give rise to state responsibility where the state did not actually participate in the commission of the harm.29

Obligations of this kind are often traced to international law’s regulation of the treatment of non-nationals.30 In the Spanish Zone of Morocco arbitration, Max Huber held that:

…the State is not responsible for the revolutionary events themselves…it may nevertheless be responsible for what the authorities do or do not do to mitigate the consequences as far as possible. Responsibility for the action or inaction of the public authorities is quite different from the responsibility for acts that may be imputed to persons outside the control of the authorities or openly hostile to them.31

The obligation to protect against harms to aliens, as a primary rule of international law, is well established.32 The nature of the obligation is revealed in diplomatic correspondence between the Italian and United States governments after the destruction of property belonging to a US citizen in Italy in 1925:33 ‘[Italy] holds itself obligated, not absolutely to prevent certain occurrences from taking place, but to exercise in order to obviate them ordinary vigilance for the protection of foreigners and citizens alike…’34 Lillich and Paxman explain that the Department of State accepted this position and informed its Embassy in Italy that a claim ought to be pursued only if it (p.130) could be shown that ‘the authorities had knowledge, or should have had knowledge of the impending attack and failed to take proper precautions to thwart it…’.35

The obligation to protect against harm to aliens may be thought of as a specific iteration of a more general principle flowing from the territorial sovereignty of the state. In the Island of Palmas arbitration, Huber expressed the principle in exactly these terms:

Territorial sovereignty, as has already been said, involves the exclusive right to display the activities of a State. This right has as corollary a duty: the obligation to protect within the territory the right of other States, in particular their right to integrity and inviolability in peace and in war, together with the rights which each State may claim for its nationals in foreign territory.36

In the Corfu Channel case, Albania’s responsibility was engaged on the basis of its failure to warn the UK of the existence of a minefield in Albanian territorial waters—every state was under an ‘obligation not to allow knowingly its territory to be used for acts contrary to the rights of other states’.37 A due diligence obligation to protect against certain harms is central to international environmental law38 and international human rights law.39 In the Bosnian Genocide case, Serbia’s international responsibility was engaged for failing to prevent the genocide at Srebrenica.40 The obligation is one of conduct, not result, and requires the state to exercise due diligence in taking all means reasonably available to prevent the harm from occurring.41

It is clear, then, that obligations of due diligence to prevent harm arise in many areas of international law. In many instances where the state has participated in the commission of harm, it will have breached the broader obligation to prevent that harm from occurring.42 So if Turkey intentionally provides information to a non-state actor in Turkey that facilitates the latter’s (p.131) killing of a journalist, it will be responsible for failing to protect the right to life under Article 2 of the European Convention on Human Rights.43 If Serbia intentionally provides logistical support to a non-state actor that facilitates the commission of genocide by that actor, its responsibility for failing to prevent genocide would certainly be engaged.44

6.3. The Role of Complicity?

If these obligations of prevention are so capacious as to encompass many situations in which a state participates in the conduct of another actor, why should a study of international law pay attention to the idea of state complicity?45 There are three reasons. First, as a matter of positive law, international law— treaty and custom—does impose certain complicity obligations on states. States and other actors articulate the responsibility of other states in terms of their complicity rather than simply their failure to exercise due diligence in preventing harms.

Second, it is not yet the case that all forms of state participation in the wrongful actions of another state or non-state actor will breach a due diligence obligation to protect against harm to other states or individuals.46 Despite the development of due diligence obligations of this kind, they largely retain their territorial character.47 Imagine that State A, with full knowledge of the circumstances, provides a credit guarantee for one of its (p.132) companies’ participation in a project carried out in and by State B.48 The project constitutes an internationally wrongful act by State B, such as a violation of its obligations to protect cultural property.49 It is not clear that the responsibility of the assisting state would be engaged under an existing obligation to protect against harm to cultural property. In the absence of a complicity rule, State A’s contribution to an internationally wrongful act would not engage its responsibility.

The third reason for paying attention to complicity goes beyond the confines of positive law. The absence of complicity rules in international law marks a lack of sophistication in the legal system.50 In Chapter 2, it was argued that complicity is a particular way of contributing to wrongdoing. This is why the language of complicity is compelling:51 it articulates and condemns a common way that states and individuals participate in the principal wrongs of others. It is not a judgment that the individual or state committed the wrong, itself or through its agents.52 Neither is it a judgment that the individual or state simply failed to take reasonable measures to protect against the harm.53 Rather, it responds to complicity as a way of contributing to wrongdoing—‘making a difference to the difference that principals make’.54

6.4. The Structure of Part C

Part C of the work (comprising this chapter and Chapters 7–9) is concerned with the complicity obligations that international law imposes on states. Chapter 7 addresses a specific rule and a general rule prohibiting state complicity in the wrongful acts of other states. It positions these rules within the analytical framework of the work and evaluates them against the normative claim set out in Chapter 2. International law now prohibits states from aiding or assisting another state in the commission of an internationally (p.133) wrongful act. This is an international analogue to municipal doctrines of accomplice liability.

Chapters 8 and 9 assess two ways that international law has dealt with the conceptual difficulty noted above concerning state participation in the harms caused by non-state actors. To recap, the conceptual difficulty is that in a system where norms are addressed to states, there is no international legal wrong committed by the non-state actor.55 Although state participation in that conduct may be (and sometimes is) prohibited directly, the conceptual possibility for derivative responsibility based on complicity is foreclosed. There is simply no wrong in which the participating state might be complicit.

International law has responded in two quite different ways to this difficulty. Chapter 8 considers the claim that complicity has penetrated the rules of attribution in international law. The idea here is not quite like the operation of a complicity rule, as defined in Chapter 2, where the complicit party is linked to the wrongdoing of another actor. Rather, the attributional idea posits that a complicit relationship is sufficient to transform the conduct of the non-state actor into state conduct. It is not that the state is held derivatively responsible in relation to another actor’s wrongdoing; rather, the conduct of that other actor becomes state conduct on the basis of its acts of support or assistance. Claims of this kind are open to principled objection and should be rejected.

Chapter 9 considers a second way that the conceptual difficulty noted above has been addressed. The conceptual difficulty is premised on the absence of legal regulation of the conduct of non-state actors. Of course, international law no longer imposes obligations only on states: individuals and other non-state actors have rights and obligations in international law. Once it is recognized that a non-state actor can violate international law, it becomes possible that a state might be complicit in that wrongdoing. Chapter 9 considers the prohibition on state complicity in genocide and raises the possibility that a non-state analogue to the general prohibition on state complicity in the wrongdoing of other states will emerge.

Together, these chapters (Part C) analyse the different ways that international law deals with state complicity. The story is one of an increasing recognition of complicity as a particular way that states contribute to wrongdoing. In respect of state participation in the wrongs committed by other states, a general complicity rule supplements existing specific rules. In respect of state participation in harms caused by non-state actors, the (p.134) obligations now imposed by international law on non-state actors have opened up the possibility of accounting for that participation as a form of complicity. Even if Ago was correct in 1939, it is not the case now that ‘any form of complicity, participation, or incitement to a delict’ is inconceivable in international law.


(1) Roberto Ago, ‘Le Délit International’ (1939) 68 (II) Recueil des Cours 419, 523 (translated). See also Aust, Complicity and the Law of State Responsibility 12.

(4) See Aust, Complicity and the Law of State Responsibility 12–15. Aust seeks to look beyond an analysis based on bilateralism and community interest in accounting for the development of complicity in the law of state responsibility.

(5) Case of the Monetary Gold Removed from Rome in 1943 (Italy v. France, United Kingdom and United States of America) (Preliminary Question) [1954] ICJ Rep 19. See also East Timor (Portugal v. Australia) [1995] ICJ Rep 90; section 7.3.8 below.

(11) Art 6 Convention concerning the Rights and Duties of Neutral Powers in Naval War (adopted 18 October 1907, entered into force 26 January 1910) 36 Stat 2415.

(13) See Legality of the Threat or Use of Nuclear Weapons (Advisory Opinion) [1996] ICJ Rep 226 [89]; Dinstein, War, Aggression and Self-Defence 176–80.

(14) Art 2(5) Charter of the United Nations (adopted 26 June 1945, entered into force 25 October 1945) 1 UNTS XVI.

(15) See Dinstein, War, Aggression and Self-Defence 176. See also Aust, Complicity and the Law of State Responsibility 158–62 for discussion of United Nations resolutions relating to non-assistance.

(17) Arts 4, 8 ARSIWA.

(21) See section 1.2 above. See also Becker, Terrorism and the State 19.

(24) UNGA Res 2625 (XXV) (24 October 1970) (Declaration on Friendly Relations).

(25) Armed Activities on the Territory of the Congo (Democratic Republic of Congo v. Uganda) (Merits) [2005] ICJ Rep 168 [162].

(27) In respect of state participation in terrorism, see UNSC Res 1373 (28 September 2001) UN Doc S/RES/1373; UNGA Res 40/61 (9 December 1985) UN Doc A/RES/40/61; UNGA Res 44/29 (4 December 1989) UN Doc A/RES/44/29; UNGA Res 49/60 (9 December 1994) UN Doc A/RES/49/60; UNGA Res 51/210 (17 December 1996) UN Doc A/RES 51/210; UNGA Res 53/108 (26 January 1999) UN Doc A/RES/53/108. See also Eric Rosand, ‘Security Council Resolution 1373, the Counter-Terrorism Committee and the Fight Against Terrorism’ (2003) 97 Am J Intl L 333; Andrea Bianchi, ‘Enforcing International Law Norms against Terrorism: Achievements and Prospects’ in Andrea Bianchi (ed.) Enforcing International Law Norms against Terrorism (Hart 2004) 491; Pierre-Marie Dupuy, ‘State Sponsors of Terrorism: Issues of International Responsibility’ in Bianchi (ed.) Enforcing International Law Norms against Terrorism 3; Ben Saul, Defining Terrorism in International Law (OUP 2006).

(28) See generally Pisillo-Mazzeschi, ‘Due Diligence’; Barnidge, The Due Diligence Principle under International Law.

(29) See Monica Hakimi, ‘State Bystander Responsibility’ (2010) Eur J Intl L 341; Olivier Corten and Pierre Klein, ‘The Limits of Complicity as a Ground of Responsibility: Lessons Learned from the Corfu Channel Case’ in Bannelier et al. (eds.) The ICJ and the Evolution of International Law 315.

(30) See Richard Lillich and John Paxman, ‘State Responsibility for Injuries to Aliens Occasioned by Terrorist Activities’ (1977) 26 Am Univ L Rev 217.

(31) Spanish Zone of Morocco Case (United Kingdom/Spain) (1923) 2 RIAA 615, 641–2.

(34) Hackworth, Digest of International Law 5 (1943) 659.

(35) Lillich and Paxman, ‘State Responsibility’ 227 citing Hackworth 660–1.

(36) Island of Palmas (Netherlands/USA) (1928) 2 RIAA 829, 839.

(37) Corfu Channel (United Kingdom v. Albania) (Merits) [1949] ICJ Rep 4, 22. See also United States Diplomatic and Consular Staff in Tehran (United States of America v. Iran) (Merits) [1980] ICJ Rep 3; Luigi Condorelli, ‘The Imputability to States of Acts of International Terrorism’ (1989) 19 Isr YB Human Rights 233, 240–1.

(38) See Trail Smelter (United States of America/Canada) 3 RIAA 1911; Karine Bannelier, ‘Foundational Judgment or Constructive Myth? The Court’s Decision as a Precursor to International Environmental Law’ in Bannelier et al. (eds.) The ICJ and the Evolution of International Law 242.

(39) See generally UNHRC, ‘General Comment 31’ (29 March 2004) UN Doc CCPR/C/21/Rev.1/Add.13 (2004) [6]‌-[8]; Velasquez Rodriguez (29 July 1988) Inter-AmCtHR (Ser C) No 4 (1988) [161]–[167]; Ireland v. United Kingdom (App 5310/71) (1978) 2 EHRR 25 [239].

(40) Bosnian Genocide [438].

(41) Bosnian Genocide [430].

(43) Cf Kiliç v. Turkey (App 22492/93) (2000) 33 EHRR 1357.

(44) See Bosnian Genocide [382]:

If a State is held responsible for [complicity in genocide] then there is no point in asking whether it complied with its obligation of prevention in respect of the same acts, because logic dictates that a State cannot have satisfied an obligation to prevent genocide in which it actively participated.

(47) See Island of Palmas; Vladyslav Lanovoy, ‘Responsibility for Complicity in an Internationally Wrongful Act: Revisiting a Structural Norm’ (SHARES Conference—Foundations of Shared Responsibility in International Law, Amsterdam, 17, 18 November 2011) 1, 7; Heathcote, ‘State Omissions and Due Diligence’ 297–9. Obligations of this kind may also arise where the state exercises effective control or jurisdiction over territory. See Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa) notwithstanding Security Council Resolution 276 (1970) (Advisory Opinion) [1971] ICJ Rep 16 [118]; Condorelli, ‘Imputability to States’ 240–1.

(49) Ibid.

(50) Ibid 13.

(53) On this point, see Antonio Cassese, ‘A Judicial Massacre’ The Guardian (London, 27 February 2007) describing the ICJ’s finding that Serbia was responsible for failing to take reasonable measures to prevent genocide from occurring, but not responsible for genocide or complicity in genocide, as a ‘consolation prize’. See also contemporaneous newspaper headlines, e.g. Beti Bilandzic and Nedim Dervisbegovic, ‘Serbs Relieved, Bosnia Dismayed by Genocide Ruling’ Reuters (Sarajevo, 26 February 2007); ‘Court Clears Serbia of Genocide’ BBC News (London, 26 February 2007).