US nuclear weapons and non-proliferation

According to a widespread conventional wisdom, there is a link between US nuclear weapons and nuclear proliferation and, therefore, in order to prevent the spread of nuclear weapons to other states, the US government must first make changes to its own nuclear arsenal. This article challenges the notion that US nuclear posture has a significant bearing on the proliferation and non-proliferation behavior of other states. Contrary to the received wisdom in policy circles, this article maintains that state decisions on nuclear non-proliferation issues are driven by a range of other security, economic, and political factors and, once these considerations are taken into account, there is little if any remaining variance to be explained by US nuclear posture. Using a dataset on US nuclear arsenal size from 1945 to 2011, this article examines the relationship between the size of the US nuclear arsenal and a variety of nuclear non-proliferation outcomes. It finds that there is no evidence of a relationship between the size of the US arsenal and: the exploration, pursuit, or acquisition of nuclear weapons by other states; the provision of sensitive nuclear assistance to non-nuclear weapon states; and voting on non-proliferation issues in the United Nations Security Council. The results are robust to alternate conceptualizations and measurements of US nuclear weapons and in various subsamples of data. This article breaks new ground on an empirical research agenda on how the nuclear policies and postures of the major nuclear powers affect the spread of nuclear weapons and has important implications for nuclear security policy.