Drawing on arguments found in international relations theory, this chapter explores Philippine nationalist resistance against imperial occupation in the late nineteenth century leading up to the Philippine–American War at the turn of the twentieth century. In particular, the chapter explores the transnational diffusion of liberal ideas among Philippine revolutionaries developed during the period of Spanish colonial rule. In hopes of securing their independence after the Spanish–American War, Filipino leaders quickly developed a constitution based on republican ideals, a legislative body, and a declaration of independence and national self-determination. Paradoxically, such ideas and actions remained unpersuasive to American policymakers. With the Treaty of Paris formally ending the war with Spain in 1898, the United States acquired its first overseas empire. In response, Filipinos resorted to guerilla warfare, drawing the United States into its “first Vietnam.”