For more than fifty years, the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and the wider nuclear nonproliferation regime have worked to prevent the spread of nuclear weapons. Analysts and pundits have often viewed the regime with skepticism, repeatedly warning that it is on the brink of collapse, and the NPT lacks many of the characteristics usually seen in effective international institutions. Nevertheless, the treaty continues to enjoy near-universal membership and high levels of compliance. This is the first book to explain why the nonproliferation regime has been so successful, bringing to bear declassified documents, new data on regime membership and weapons pursuit, and a variety of analytic approaches. It offers important new insights for scholars of nuclear proliferation and international security institutions, and for policymakers seeking to strengthen the nonproliferation regime and tighten international constraints on the spread of nuclear weapons.

‘This book makes an essential contribution to our understanding of nuclear nonproliferation. Many studies of nuclear proliferation have either ignored the Non-Proliferation Treaty (NPT) or found the treaty to be ineffective. Jeffrey Kaplow persuasively demonstrates that those who dismiss the NPT get it wrong. By elaborating on theories about how international institutions provide information, examining government deliberations in some key cases, and employing multiple quantitative tests, Kaplow shows that the NPT has slowed proliferation while also highlighting other features of the nonproliferation regime that have been less constraining, including the inconsistency of enforcement against violators and the role of the NPT in fostering nuclear latency. Kaplow's conclusion that the nonproliferation regime has been “both successful and fragile” points to a need for states to renew their efforts to strengthen the NPT.'

Jeffrey W. Knopf - Professor and Program Chair, Nonproliferation and Terrorism Studies, Middlebury Institute of International Studies at Monterey