Third or “Second and a Half”? Continuity, Path Dependence, and the Third Nuclear Age

ABSTRACT The world has entered a new nuclear age. Scholars have characterized this “third nuclear age” as one of renewed competition among nuclear‐armed great powers and the coming maturation of new technologies. I trace the origins of the new nuclear age. Focusing primarily on US strategies with two case studies on conventional strike capabilities and missile defense and briefly examining how Russia and China respond with their nuclear buildups, I argue that the new age is not simply a renewed Cold War‐like competition with more advanced technologies. Instead, the new nuclear age shows significant path dependency from post‐Cold War US strategies against rogue states. It inherits a strategic focus on regional contingencies and the interplay between nuclear deterrence and “conventional counter‐deterrence.” The latter seeks to deny nuclear‐armed US adversaries the ability to deter US regional intervention by undermining their nuclear deterrence capabilities. While these strategies enhance US conventional superiority, they also fuel an arms race in peacetime and heighten contention in crises.