Since the end of World War II, the USA has maintained a sizable military presence around the world. As one of the main mechanisms that the USA uses to exercise its military power abroad, it is a defining characteristic of the international order. Using time-series cross-sectional models and case evidence, I show that, in addition to strategic considerations, the President’s party strength in Congress and the proportion of moderates in the Senate are key determinants of US deployment outcomes. This finding adds to the literature on causes of US troop deployments by examining the incentives for deployments within US politics.