First important national labour organization in the U.S. Founded in 1869 by capitalism .
To protect its members from employers' reprisals, it originally maintained secrecy. Under Terence V. Powderly (1879–93) it favoured open {{link=arbitration">arbitration with management and discouraged strikes. National membership reached 700,000 in 1886. Strikes by militant groups and the Haymarket Riot caused an antiunion reaction that rapidly reduced the organization's influence. A splinter group left to form the AFL (later AFL-CIO ).