Lewis, John Llewellyn, 1880–1969, American labor leader, b. Lucas co., Iowa son of a Welsh immigrant coal miner. He became a miner and after 1906 rose through the union ranks to become president (1920) of the United Mine Workers of America (UMW). Forceful and determined, Lewis fought vigorously to build up the union, won the loyalty of the miners, and thus consolidated his own power. He was one of the most important figures in the American Federation of Labor (AFL) until, moved by the desire to unionize the mass production industries, he split with the AFL and its leader, William Green. Taking several of the largest unions with him, Lewis founded (1935) a new organization, the Committee for Industrial Organization (CIO see American Federation of Labor and Congress of Industrial Organizations ). He had supported Franklin Delano Roosevelt for President in 1932 and had welcomed the New Deal, but coolness developed between Lewis and Roosevelt, and in 1940 Lewis supported Wendell Willkie for the presidency and staked his CIO presidency on Willkies victory. Roosevelt won, and Lewis resigned. Increasing antagonism between him and Philip Murray, the new head of the CIO, led to a break, and in 1942 the UMW withdrew from the CIO. Lewis kept his own power. During World War II, Lewis was faced with the hostility of the War Labor Board and with unfavorable public sentiment because of the many strikes of the coal miners in the no-strike period. Although these strikes may have helped to pave the way for antistrike legislation, they did win the demands of the miners. The UMW was again joined (1946) to the AFL but split off (1947) once more in a dispute over means of combating the restrictive Taft-Hartley Act. Lewiss failure to obey a federal court order to end a protracted coal strike led (1948) to a heavy fine for criminal contempt of court. In the 1950s Lewis discontinued his more aggressive tactics and followed a policy of accommodation with the depressed coal industry. He resigned as president of the UMW in 1960.