What roles have nuclear nonproliferation and counterproliferation played in U.S. grand strategy since 1945? 1 And what insights does this history provide into the sharp, contemporary debates over the past, present, and future trajectory of U.S. grand strategy?Most accounts of postwar U.S. grand strategy focus on two broad but distinct missions: (1) to contain great power rivals and (2) to open the world's economy and political systems to encourage the ºow of trade, resources, and capital.2 There has been considerable debate over the origins, continuity, and effectiveness of both the containment and openness missions, and over identifying when these strategies have been at odds and where they have overlapped.