Over 60 years ago the USA agreed to give up its autonomy over the use of force by signing the UN Charter. Prof. Hurd uses this case study to better understand how states use international rules and how that use remakes both the rules and the states. Over 60 years ago the United States agreed to give up its autonomy over the use of force by signing the United Nations Charter, which includes a ban on war in Article 2(4). The willing self-limit by a Great Power of its sovereignty over war decisions contradicts the realist expectation that states, especially strong ones, will enhance and guard their autonomy. It also presents a puzzle for rationalists and constructivists and their competing models of the relationship between state interests and international norms. These models suggest that states either follow their interests or follow norms which they have internalized. The former makes all behavior 'strategic' and the latter makes it norm-compliant and unconcerned with interests. Neither side can account behavior where decision-makers apparently believe genuinely in the rule but continued to think and act strategically around it. The U.S. position toward Article 2(4) is an example of this broad category in foreign policy. To understand such cases we must bridge the divide between norms and interests, and between rationalism and constructivism, by focusing on how states use international rules and how that use remakes both the rules and the states.