The Iraq War has received little sustained analysis from scholars of international relations. I assess the rationalist approach to war—or, simply, bargaining theory—as one possible explanation of the conflict. Bargaining theory correctly directs attention to the inherently strategic nature of all wars. It also highlights problems of credible commitment and asymmetric information that lead conflicts of interest, ubiquitous in international relations, to turn violent. These strategic interactions were central to the outbreak of the Iraq War in 2003. Nonetheless, bargaining theory is inadequate as an explanation of the Iraq War. Although the problem of credible commitment was real, it could not be solved because of the prior beliefs of the Bush administration that Saddam Hussein was uniquely evil and because of Saddam's inability to signal accurately to multiple audiences, both factors now outside bargaining theory. Nor was the problem of private information an important impediment to bargaining; rather, the information failures observed in both Washington and Baghdad were of their own making as each formed self-deluding beliefs and expectations. Bargaining theory also ignores postwar governance costs and domestic interest groups, both of which contributed to the war. All of these problems require either considerable amendments to the theory or the revision of core assumptions. Drawing on this critique, the final sections draw out the analytic and policy lessons of the Iraq War and suggest, most importantly, the need for a new behavioral theory of war.