In the last decade, the field of international relations has undergone a revolution in conflict studies. Where earlier approaches attempted to identify the attributes of individuals, states, and systems that produced conflict, the “rationalist approach to war” now explains violence as the product of private information with incentives to misrepresent, problems of credible commitment, and issue indivisibilities. In this new approach, war is understood as a bargaining failure that leaves both sides worse off than had they been able to negotiate an efficient solution. This rationalist framework has proven remarkably general—being applied to civil wars, ethnic conflicts, and interstate wars—and fruitful in understanding not only the causes of war but also war termination and conflict management. Interstate war is no longer seen as sui generis, but as a particular form within a single, integrated theory of conflict.