Rank-and-file movements in labor unions have shaped the terrain of labor struggle in recent years. Some have served primarily as “reform” vehicles for a wing of the union bureaucracy, while others have anchored rank-and-file struggles on the shop floor with a reinvigorated class-struggle vision. UAW President Shawn Fain and Teamsters President Sean O’Brien represent the culmination of two prominent union reform movements in recent years, but their promise of increased militancy and new organizing has yielded mixed results. How can we build class-struggle unions capable of confronting the state and capital?