Nuclear weapons challenge traditional moral and political categories for the evaluation of war. This book argues that political and technological changes have demonstrated the inadequacy of both just war theory and political realism in relation to modern war, and examines how these changes have transformed the way in which war is conceived and fought. War with nuclear weapons is no longer a contest of military strength but a bargaining process characterized by the manipulation of risk. Current thinking often rests on an outdated understanding of war. This unique book spans the disciplines of history, ethics, and international relations theory in its search for an adequate response to the criminal burden of nuclear weapons.