Anti-U.S. base protests, played out in parliaments and the streets of host nations, continue to arise in different parts of the world. In a novel approach, this book examines the impact of anti-base movements and the important role bilateral alliance relationships play in shaping movement outcomes. The author explains not only when and how anti-base movements matter, but also how host governments balance between domestic and international pressure on base-related issues. Drawing on interviews with activists, politicians, policy makers and U.S. base officials in the Philippines, Japan (Okinawa), Ecuador, Italy and South Korea, the author finds that the security and foreign policy ideas held by host government elites act as a political opportunity or barrier for anti-base movements, influencing their ability to challenge overseas U.S. basing policies.