Using the racial integration of national labor unions as a case study, I find that courts played an important and meaningfully autonomous role in integrating unions while elected officials largely failed to act. Courts, unlike elected officials, offered civil rights groups relatively easy access to the legal agenda. In response to thousands of cases in federal courts, judges rewrote key civil rights statutes, oversaw the implementation of their rulings, and used attorneys' fees and damage awards to impose significant financial costs on resistant unions. Court power was the product of multiple and historically contingent forces that involved the interaction of elected officials, civil rights activists, and the legal community. Elected officials delegated to the courts the power to enforce civil rights laws and tacitly endorsed procedural changes that augmented the courts' institutional powers and the legal community's professional influence. In response, judges and lawyers promoted and implemented a civil rights agenda far beyond the endorsement of elected officials. An historical–institutional approach helps explain how courts achieved and wielded independent power and the consequences of their action for civil rights, labor unions, and the American state.Thanks for very helpful comments go to Amy Bridges, Kerstin Carlson, Malcolm Feeley, Beth Garrett, Howard Gillman, Mark Graber, Jeff Haydu, David Karol, Ken Kersch, David Mayhew, Jim Morone, Shehzad Nadeem, Ruth O'Brien, Corey Robin, Pam Singh, John Skrentny, Mark Tushnet, Rick Valelly, Keith Whittington, Janelle Wong, the APSR reviewers, and Lee Sigelman. The University of California's Institute for Labor and Employment provided generous financial assistance.