The book studies how U.S. military deployments abroad serve as a tool of public diplomacy that can both support and undermine the international liberal order established by the United States. It develops and systematically tests a theory of public opinion toward the United States, its people, and its global non-invasion military deployments. Positive interactions with servicemembers, including routine daily interactions and the economic flows from a deployment, serve as a form of public diplomacy, improving perceptions of military deployments and the United States as a whole. However, negative events and experiences stemming from deployments, like crime, pollution, and controversial mission types can produce negative reactions among local populations. The book explores these subjects, including chapters devoted to understanding how different forms of contact, reported experiences with crimes involving US service members, and belonging to minority communities, all affect views of the US military presence in a state. We The book also looks at how these factors shape reported involvement in protests against the US, and broader trends in anti-US protest events around the world. The book argues that curtailing servicemember engagement in the community is a policy that can backfire on the US military's long-term objectives, as removing day-to-day positive social interactions with US personnel diminishes one of the main sources of goodwill toward US deployments. It proposes that US policy should focus not on isolating deployed forces from local populations but on regulating interactions in a way that maximizes the potential for beneficial social connections and minimizes harm to host populations.