Nuclear Posture, Nonproliferation Policy, and the Spread of Nuclear Weapons

Abstract

What is the relationship between nuclear postures and nonproliferation policies and the spread of nuclear weapons? At first blush, this might appear to be an obvious question. After all, states go to great lengths—extending nuclear security guarantees to nonnuclear weapon states, forward-deploying nuclear weapons on the territory of allies, sizing their own nuclear arsenals with the proliferation decisions of other states in mind, supporting international institutions in conducting inspections of nuclear facilities in nonnuclear weapon states, restricting the availability of sensitive nuclear technology, applying and enforcing sanctions against would-be proliferators, conducting military strikes against nuclear facilities, and promoting nuclear cooperation for peaceful purposes, among many other steps—to prevent the spread of nuclear weapons. It would be strange to imagine that states pursue such actions unless they can expect a policy payoff in terms of peace or security. Yet, there is little systematic evidence to suggest that nuclear postures and policies have a meaningful impact on the spread of nuclear weapons. Correctly understanding the effects of nuclear posture and policy on both horizontal proliferation (the spread of nuclear weapons to new states) and vertical proliferation (increases in the size and sophistication of nuclear arsenals within existing nuclear states) is a subject of extreme real-world importance. United