Building the Deportation Regime unpacks the transnational dimensions of US deportation practices during the interwar period, highlighting the challenges faced by American policymakers as they sought to enforce deportation in an increasingly complex global landscape of migration. Emily Pope-Obeda argues that a deportation order is merely the starting point for extensive international contact, coordination, and, frequently, conflict. Building the Deportation Regime highlights all that is needed to enable deportation: collaboration with the US foreign policy apparatus, communication with foreign officials, documentation and surveillance of migrants both within and beyond US borders, and the geopolitical power to enforce international compliance. Efforts to expand the deportation regime exposed the limits of state power and the conflicting visions of the state held by different branches of the US government. As Pope-Obeda demonstrates, deportation practice, as opposed to policy, operates with one eye looking outward. On-the-ground deportation enforcement necessitated a broad state-building project. Throughout the interwar period, the United States built a multisited immigration bureaucracy reaching everywhere US consular representatives were stationed.