Poor Man’s Atomic Bomb? Exploring the Relationship between “Weapons of Mass Destruction”

The causes and consequences of nuclear proliferation have received a great deal of academic attention. However, nuclear weapons are rarely discussed in isolation in policy circles. Instead, nuclear weapons are relevant as part of a category of weapons of mass destruction (WMDs) that includes chemical and biological weapons (CBWs). Are the factors that drive CBWs proliferation similar to those that drive nuclear proliferation? What is the relationship between these weapons types? In this article, we explore whether nuclear weapons and CBWs serve as complements or substitutes. Using newly collected data on both CBWs pursuit and possession over time, we find that nuclear, biological, and chemical weapons generally function as complements at the pursuit stage. In addition, countries that acquire nuclear weapons become less interested in pursuing other types of WMDs and are even willing to give them up in some cases.