This dissertation investigates how music making shapes political participation during periods of democratic crisis and authoritarianism. It examines the musical theater production Opinião, which was staged nightly in Rio de Janeiro from December 1964 to April 1965 at the onset of the Brazilian military dictatorship. Rather than examining Opinião as the reflection of its director's or authors' politics, I take an intersectional approach that focuses on the performers and audience members, who came from different gender, racial, geographic, and class backgrounds. Through an analysis of the show's performances, I demonstrate how people from diverse populations enacted political protest. I put their diverse strategies for intervening in the Rio de Janeiro public sphere into dialogue with one another to demonstrate how authoritarian regimes impact different sectors of society. My inquiry combines both ethnographic and archival research methods. I draw on hundreds of archival documents and recordings—including newspaper and magazine clippings, theater programs, advertisements, and other ephemera—to reconstruct details of the show and investigate in depth the discourse that the show engendered. I argue that notions of authenticity were instrumentalized by critics and audiences to evaluate not only the performances in the show, but also the participants' politics. In addition to archival materials, I draw on interviews I conducted with participants and audience members of Opinião, thereby including the impressions of people whose ideas were not included in the written record. In my analyses of Opinião's songs and performances, I listen for the aspects of the performances that attendees identified as important. By combining musical analysis with an investigation of the political discourse around Opinião, I illustrate how politically oriented music making is bound up with issues of power, and how musicians employ a variety of strategies in the face of myriad limiting factors.