This book represents one of the first comparative studies of international treaty ratification processes in multiple issue areas. The study sets out to fill a gap in political science scholarship by investigating the role that international and domestic political actors and conditions play in the critical, post-commitment phase of cooperation. The book employs the comparative case study method, drawing on original research, elite interviews, and discursive analyses of government documents in Europe, Australia, and North America. Cases examine a select number of treaties on trade cooperation, the environment, European integration, and the nuclear non-proliferation regime. The book concludes that norms and executive strategies play an especially significant role in shaping ratification outcomes. The study has implications for theories of international negotiation and foreign policy analysis as well as the practice of diplomacy.