Rethinking Ratification: Legalization and Nuclear Weapon Free Zone Treaties

Abstract

Why do countries ratify international treaties‘ To what extent is ratification contingent on the creation of agreements‘ To address these questions, this article examines the creation and ratification of regional nuclear weapon free zone (NWFZ) treaties, which prohibit the development, testing, deployment, and transit of nuclear weapons. We argue that states establish NWFZs when they have little interest in the future development of nuclear weapons, since nonproliferation commitments are relatively cheap under such circumstances. We also hypothesize that the actual terms of the treaty have little to do with ratification. Countries ratify NWFZ treaties when their neighbors do so as a result of norm diffusion. Statistical tests employing a Heckman probit selection model lend strong support to the hypotheses. The findings help resolve a debate in the literature on treaty ratification and have important implications for research on selection effects and legalization. They also suggest that NWFZ treaties can be viable nonproliferation tools, but only in regions where there is a relative absence of militarized conflict.

Keywords: international law, treaty ratification, nuclear nonproliferation, nuclear weapon free zones, selection effects