Hegemony and nuclear proliferation

Abstract

Contrary to longstanding of predictions of nuclear tipping points, the number of states interested in nuclear weapons has sharply declined in recent decades. In contrast to existing explanations, this dissertation argues that the decline is largely attributable to US nonproliferation policies, in particular the threat of sanctions that was instituted in the late 1970s. By credibly threatening to cut off economic and military support to countries pursuing nuclear weapons, I argue that this threat of sanctions deters states within the US sphere of influence from proliferating, reducing the overall rate of proliferation and also explaining why recent nuclear aspirants have exclusively been "rogue" states outside the US sphere of influence. Because states that depend on the United States have been deterred from proliferating in recent decades, the observed success rate of sanctions should be low, since they will generally be targeted at states that do not rely on US resources. This dissertation also offers a theory of the sources of US nonproliferation policy, arguing that fears of nuclear domino effects are necessary to explain (1) why US policy strengthened so dramatically in the wake of Chinese and Indian nuclear tests in the 1960s and 1970s, and (2) why the US abandoned a selective nonproliferation policy and decided to enforce nonproliferation across the board. To test these two arguments, this dissertation employs a mix of quantitative and qualitative methods. First, I draw on archival documents to show that fears of nuclear domino effects motivated US nonproliferation policy advances in the 1960s and 1970s, and that this motivation was prominent in individual cases of nonproliferation. Second, I show quantitatively that states dependent on the United States have been less likely to pursue nuclear weapons since sanctions policies were instituted in the late 1970s, that observed cases of sanctions have been largely ineffective, and that the deterrent effect of sanctions largely accounts for the temporal decline in proliferation. Case studies of US policy toward Pakistan and Taiwan demonstrate that a credible threat of sanctions can arrest ongoing nuclear programs when the proliferator is dependent on the United States and underestimated the likelihood of sanctions.