This project explores the role of the extreme Right in fostering and structuring state violence and repression during Brazil's military dictatorship (1964–1985). In a mid-Cold War pattern that would soon overtake the continent, the Brazilian military seized and held power in the name of countersubversive (anticommunist) national security. As generations of scholars have made clear, "subversion" thus functioned as a constant, theoretical and justificatory enemy against which the Brazilian regime (like its nearby counterparts) unleashed state-sponsored terror, torture, and murder. Yet we still know relatively little about how subversion was constructed and comprehended by those who so violently sought to combat it—and how such construction lent military government its ferocity and tenacity. This dissertation argues that Brazilian military rulers and their conservative supporters envisioned the Cold war primarily as a culture war; that the record of security theory and policy-making reveals a 1960s and 1970s revivification of reactionary prerogatives from decades past; and that concern about gender, moral, and sexual deviance, as well as about modernity itself, informed state ideology and repressive agendas.