In an obiter dictum in its 1970 judgment in the Barcelona Traction case, the International Court of Justice identified a category of international obligations called erga omnes, namely obligations owed by states to the international community as a whole, intended to protect and promote the basic values and common interests of all. Without losing sight of the theoretical dimension of obligations erga omnes, this book adopts a pragmatic approach, attentive to the traditional sources of international law and evaluating obligations erga omnes in light of state practice and court decisions (includi ... More

In an obiter dictum in its 1970 judgment in the Barcelona Traction case, the International Court of Justice identified a category of international obligations called erga omnes, namely obligations owed by states to the international community as a whole, intended to protect and promote the basic values and common interests of all. Without losing sight of the theoretical dimension of obligations erga omnes, this book adopts a pragmatic approach, attentive to the traditional sources of international law and evaluating obligations erga omnes in light of state practice and court decisions (including the South West Africa and the Nuclear Tests cases). After discussing a broad spectrum of key international concepts, including jus cogens, objective regimes, and state servitudes, the book analyzes the four examples of obligations erga omnes given by the International Court in its obiter dictum on obligations erga omnes: the prohibition of aggression and genocide, and the protection from slavery and racial discrimination. From this analysis, the book infers five common elements of obligations erga omnes, including their reflecting basic moral values. The book then examines these common elements in light of other candidates of obligations erga omnes proposed in the international literature and state practice. Before drawing general conclusions, the book addresses the relationship between erga omnes and jus cogens, and between erga omnes and actio popularis.