Coercive nonproliferation: Security, leverage, and nuclear reversals

This dissertation explains when countries with nuclear weapons ambitions comply with or defy foreign demands that they abandon their bomb aims and accept restrictions on their nuclear progress. It argues that the likelihood of compliance with nonproliferation demands depends on the aspirant's military security environment and the sender's use of coercive leverage. Insecurity determines the benefits of armament --- the higher a country's probability of experiencing military defeat resulting in loss of territory or sovereignty, the more it will require nuclear weapons for deterrence. Coercive leverage determines the countervailing cost of nuclear ambitions --- the more leverage the sender brings to bear, the greater the incentive for restraint. Aspirants are expected to comply when the value of the coercer's promises and threats exceeds the benefits of nuclear acquisition.;By identifying the determinants of nonproliferation success, this dissertation challenges the prevailing academic consensus that superpower coercion is incidental to nuclear reversals. With few exceptions, scholars have accepted the pessimistic view of Kenneth Waltz, who argued that "in the past half-century, no country has been able to prevent other countries from going nuclear if they were determined to do so." Instead, nonproliferation researchers have turned to ideational and domestic political factors to explain nuclear restraint. As Jacques Hymans notes, "the overwhelming majority of scholarly work on nuclear proliferation argues that states do not directly respond to the international environment in making their nuclear weapons choices." By contrast, this dissertation contests the notion that nuclear restraint can only be understood by examining changes in ideology, norms, and domestic politics. Instead, by explaining how security and leverage govern the effect of foreign nonproliferation demands, it identifies the contours of superpower influence and integrates coercion into understandings of nuclear restraint.;To test its predictions against competing models, this dissertation employs historical process tracing on a representative sample of nuclear aspirants: West Germany, Libya, South Africa, and Pakistan. Process evidence from these cases indicates that countries' choices were driven by a combination of military insecurity and U.S. coercive pressure, contradicting competing explanations and bolstering this dissertation's theoretical framework.