Bipartisan consensus on many US domestic and foreign policy priorities has seemingly collapsed in recent decades, and political parties have become qideologically polarized and divided. While some contend that these dynamics are narrowing the space for congressional foreign policy innovation, we argue that factionalism often fosters creativity in the foreign policy process. Specifically, this article explores the role of ‘free agent’ progressive Democrats and conservative Republicans in foreign policy decision-making. These members at the ideological extremes of their parties are finding common ground in anti-establishment views and concerns about executive excess, and they are aligning to challenge traditional foreign policy positions. This paper conducts a plausibility probe of a model of congressional foreign policy free agency based upon roll call voting on war powers-related decisions in the Obama and Trump administrations. During both presidencies, our findings suggest that the free agency model has predictive value for foreign policy maneuvering and offers a non-traditional way of thinking about contemporary US foreign policy development.