Does state acquisition of nuclear weapons lead to stability and peace or instability, conflict and dangerous crises? This is one of the great debates in International Relations scholarship. Michael D. Cohen argues that nuclear weapons acquisition often does dangerously embolden the acquiring state to undertake coercion and aggression, but that this behavior moderates over time as leaders learn the dangers and limitations of nuclear coercion. The psychological impact of experiencing a nuclear crisis and then regaining control of the situation changes their behavior over time. This book examines the historical cases of the Soviet Union and Pakistan in depth and also looks at mini-cases that involved the United States, China, and India to make this argument. This book broadens our understanding of how leaders and states behave when they acquire nuclear weapons, and it is important reading for scholars and students of international relations, security studies, and political psychology.