Nuclear weapons and foreign policy

Abstract

How do states change their foreign policies when they acquire nuclear weapons? This question is central to both academic and policy debates about the consequences of nuclear proliferation, and the lengths that the United States and other states should go to to prevent proliferation. Despite this importance to scholars and practitioners, existing literature has largely avoided answering this question. This dissertation aims to fill this gap. In answering this question, I first offer a typology of conceptually distinct and empirically distinguishable foreign policy behaviors that nuclear weapons may facilitate. Specifically, I distinguish between aggression, expansion, independence, bolstering, steadfastness, and compromise. The typology allows scholars and practitioners to move beyond catch-all terms such as "emboldenment" when thinking about how states may change their foreign policies after nuclear acquisition. Second, I offer a theory for why different states use nuclear weapons to facilitate different combinations of these behaviors. I argue that states in different geopolitical circumstances have different political priorities. Different states therefore find different combinations of foreign policy behaviors attractive, and thus use nuclear weapons to facilitate different foreign policy behaviors. The theory uses a sequence of three variables-the existence of severe territorial threats or an ongoing war, the presence of senior allies, and the state's power trajectory-to predict the combinations of foreign policy behaviors states will use nuclear weapons to facilitate. Third, I test the theory using case studies of the United Kingdom, South Africa, and the United States, each drawing on interviews and multi-archival research. In each case, I look for discontinuities in the state's foreign policy behaviors that occur at the point of nuclear acquisition and use process tracing to assess whether nuclear weapons caused the changes observed. The dissertation makes several contributions. It provides an answer to a foundational question about the nuclear revolution: how do states use nuclear weapons to facilitate their goals in international politics? It offers a new dependent variable and theory with potentially broader applicability to other questions about comparative foreign policy. Finally, it offers policy-relevant insights into how new nuclear states might behave in the future.