The Limits of International Law sets forth a general theory of international law. The book rejects the traditional explanations of international law based on legality, morality, opinio juris, and related non-instrumental concepts. Using simple rational choice tools, the book seeks instead to provide an instrumental account of when and why nations use international law, when and why they comply with it, and when and why international law changes. The basic descriptive story is that international law emerges from and is sustained by nations acting rationally to maximize their interests (i.e., their preferences over international relations outcomes), given their perception of the interests of other states, and the distribution of state power. ...