This paper uses a Darwinian perspective to examine the nuclear arms race in the context of “arms races” in evolution and throughout human history. The rise of human “arms races,” or escalatory intergroup competition, is traced to a variety of environmental triggers initiated during the Terminal Pleistocene/Early Holocene. These triggers removed extraspecific environmental constraints to escalatory intergroup competition in some areas of the world, making it reproductively advantageous for individuals to live in increasingly larger and more competitive groups. This process is linked to the development of social complexity and the intensification of intergroup competition, warfare, and arms production, culminating in the nuclear arms race. Historically, escalatory intergroup competition has been reproductively advantageous to elites because it enables them to acquire a disproportionately large share of resources. It is argued that the continuation of the nuclear arms race past a level of mutual assured destruction results from the benefits it provides to elites as well as a variety of evolved behavioral mechanisms that encourage in-group affiliations, out-group hostilities, and obedience to authority.