What is the effect of the spread of nuclear weapons on international politics? The scholarly debate pits proliferation optimists, who claim that “more may be better,” against proliferation pessimists, who argue that “more will be worse.” These scholars focus on the aggregate effects of nuclear proliferation, but never explicitly consider the differential effects of the spread of nuclear weapons. In other words, they do not examine whether nuclear proliferation may threaten some states more than others. I propose a theory of nuclear proliferation that examines the differential effects of nuclear proliferation. I argue that the threat nuclear proliferation poses to a particular state depends on that state’s ability to project military power. The spread of nuclear weapons is worse for states that have the ability to project conventional military power over a potential nuclear weapon state primarily because nuclear proliferation constrains their conventional military freedom of action. On the other hand, nuclear proliferation is less threatening to, and can sometimes even improve the strategic environment of, states that lack the ability to project power over a potential nuclear weapon state, because the spread of nuclear weapons disproportionately constrains other, more powerful states. This article contributes to our understanding of the consequences of nuclear proliferation and contains important implications for nuclear nonproliferation policy.
Excerpt from the Conclusion:
In short, U.S. officials need to understand the difficulty to get international nuclear nonproliferation cooperation for what it is: nuclear proliferation threatens the United States more than any other state on the globe. The United States is a global superpower and nuclear proliferation anywhere threatens America’s dominant strategic position. For other states, with more limited spheres of influence, nuclear proliferation in a distant region is not a threat. In fact, these countries may even see a significant upside to the spread of nuclear weapons — because nuclear proliferation means a constrained and thus weakened United States. Foreign governments’ reluctance to bear a burden to stop proliferation in a distant region is not the result of their failure to understand the strategic consequences of nuclear proliferation; it is because they understand them perfectly well. The failure of understanding is on the U.S. side. Washington will continue to struggle to convince other states to join in a fight against nuclear proliferation that disproportionately threatens the United States.
Matthew Kroenig is an assistant professor in the Department of Government at Georgetown University and a research affiliate with The Project on Managing the Atom at Harvard University. “Beyond Optimism and Pessimism: The Differential Effects of Nuclear Proliferation” was published as part of the “Managing the Atom Working Paper Series” (Working Paper No. 2009-14) in November 2009.