When Rep. Hilda Solis inserted remarks in the Congressional Record praising Los Angeles activist John Pérez as "an asset to the labor movement," she was recounting the life story of a man who would later become California's Assembly speaker. "After graduating from the University of California Berkeley, John began working on designing and organizing education programs," Solis, then a Los Angeles congresswoman and now U.S. secretary of labor, wrote in 2004. But the record is wrong: Pérez dropped out of UC Berkeley and never returned. For a decade, Pérez's designation as a UC Berkeley graduate went unchallenged in newspaper articles,...