Through migrant and activist testimonies, media coverage, and government documents, this article explores the modes of resistance inside and outside of immigration detention that arose in response to new, more punitive detention policies enacted by the Reagan administration that specifically targeted Caribbean and Central American asylum-seekers in the early 1980s, and the modes of retaliation adopted by the administration in response. It argues migrant detention operates as a form of counter-insurgency, re-centering the geopolitics of asylum within the transnational scope of counter-insurgent warfare and its role in the rise of carceral trends more broadly. Reagan’s “Cold War on immigrants”—defined as a suite of new immigration enforcement measures that was adopted by the Reagan administration during its first term and buttressed the subsequent growth of the detention system—sparked mass resistance. Mounting public dissent against Reagan’s foreign and immigration policies, as evidenced by “inside-outside” and transnational activism, Jesse Jackson’s 1984 presidential campaign, and the Central America peace and Sanctuary movements, prompted the administration to wage a total war against its opponents to maintain its immigration control and foreign policy aims. The contemporary US immigration detention system emerged, and continues, out of this dialectic of resistance and retaliation.