Examining the social and intellectual collision of the American reform tradition with immigrant Marxism during the Reconstruction era, Timothy Messer-Kruse charts the rise and fall of the International Workingman's Association (IWA), the first international socialist organization. He analyzes what attracted American reformers--many of them veterans of antebellum crusades for abolition, women's rights, and other radical causes--to the IWA, how their presence affected the course of the American Left, and why they were ultimately purged from the IWA by their orthodox Marxist comrades. Messer-Kruse explores the ideology and activities of the Yankee Internationalists, tracing the evolution of antebellum American reformers' thinking on the question of wage labor and illuminating the beginnings of a broad labor reform coalition in the early years of Reconstruction. He shows how American reformers' priority of racial and sexual equality clashed with their Marxist partners' strategy of infiltrating trade unions. Ultimately, he argues, Marxist demands for party discipline and ideological unity proved incompatible with the Yankees' native republicanism. With the expulsion of Yankee reformers from the IWA in 1871, American Marxism was divorced from the American reform tradition.