Why is the United States widely viewed as losing wars it fights against insurgents? Especially since Vietnam, it is a commonly held perception that the US wins wars it fights against states, but it loses wars it fights against insurgencies, a viewpoint reinforced by the current difficulties in Iraq. This paper tests three competing explanations for this ?quagmire? mentality. The first is that all major states fare badly in wars against insurgents. The second explanation holds that the US does indeed lose more often against insurgencies than other states, due to tactical weaknesses, cultural attitudes, and the US democratic system. However, a major part of the explanation is provided by a third, and completely novel, argument: often, the US does not meaningfully lose against insurgents, but is nevertheless perceived as having lost. American observers tend to evaluate US counter-insurgency operations with an extremely unforgiving yardstick for measuring success. A fair evaluation of success would focus on material outcomes and the achievement of aims, as well as the costs and benefits of not intervening. However, many evaluations of US wars against insurgents are based on whether or not the standards of American democracy are replicated abroad. To be judged as a success, therefore, a US intervention must not only destroy the insurgency, it must create political stability, and construct a democratic government. Utilizing this yardstick for US success, ambiguous outcomes in civil wars are usually seen as outright defeats. The Vietnam War Tet Offensive in 1968 and the Somalia intervention in 1993 are prime examples of at least partial successes perceived, nevertheless, as failures. In 2003 in Iraq, the American public?s view of US success fell dramatically as soon as the conflict shifted from an inter-state war to a counter-insurgency operation, strongly suggesting that a different set of subjective criteria are employed to judge success in these two types of conflict. The unforgiving standards for determining success result in part from the rhetoric of democratic reform often employed by US leaders to build support for interventions in internal wars; rhetoric which forms the basis for later negative evaluations. Furthermore, Vietnam was a searing experience for the United States, and strongly entrenched the ?lesson? that the US loses in quagmire wars against shadowy insurgents. Often, perceptions of failure are a self-fulfilling prophecy, with negative elite and public attitudes leading to US disengagement, and a very real failure on the ground.The paper uses a number of different sources and methodologies, including experimental analysis of American perceptions of counter-insurgency operations. This paper is based in part on research for my forthcoming book, tentatively entitled Victory and Defeat in International Relations (Harvard University Press, 2006), co-authored with Dominic Johnson, which explains more generally the subjective processes by which people decide which country won and lost in wars and crises. ..PAT.-Conference Proceeding [ABSTRACT FROM AUTHOR]