Almost twenty years old, the constructivist turn in international relations scholarship has succeeded in demonstrating the effects of norms, both in guiding the interactions of states with one another as well as influencing the domestic political debates that give rise to foreign policy outcomes. More recently, scholars have begun to study empirically the interactions between international and domestic normative systems. The origins of many international norms have been located in national understandings of what constitutes appropriate behaviour in a given issue area. The reverse, however, is also held to be true. Many national-level norms have been adopted after first finding their articulation in international institutions.