Despite the end of the Cold War more than two decades ago, and with it the high risk nuclear rivalry between the Soviet Union and the United States, nuclear weapons—and the associated concerns of proliferation—remain an important issue in international relations. Under the right conditions these weapons can serve as effective deterrents, increasing the stability of the international system. Under the wrong conditions, however, nuclear weapons can decrease regional stability and produce a more conflictual international system. This is especially likely during the difficult and risky path to acquisition, as several chapters in this volume make clear. Contrary to much of the received wisdom about the utility of nuclear weapons, possession can also lead to reduced security—especially if weapons are poorly integrated into a country’s force structure or military doctrine.