A vigil, sit-in, demonstration, or protest is taking place outside a U.S. base somewhere around the world at this very moment. Do these pockets of protest, varying in size, shape, and form, make any difference in base politics? When and how do anti-base movements matter? How do host governments react to anti-base opposition with U.S. security relations at stake?

Unfortunately, existing theories of international relations are ill equipped to help us understand when and how anti-base movements matter. Nor do they help us accurately predict the type of response produced by host states when balancing between international and domestic forces. For instance, a realist approach to base politics contends that, regardless of domestic opposition, bases are likely to endure if national security interests are at stake. But empirical examples – most notably the closure of the strategically important Subic Bay Naval Station in 1991 – pose significant problems for realism. Commonly explored concepts in international relations, such as the balance of power, threat perceptions, or alliance relations, certainly shape basing policy decisions. However, an analysis of overseas bases at the systemic level fails to capture the dynamics of base politics played across two boards (the domestic and international levels) with three players (the United States, host government, and civil society).