The Congress of Industrial Organizations (CIO), now part of the AFL-CIO, is a coalition of American labor unions formed by John L. Lewis and Sidney Hillman in the mid 1930s from breakaway unions that previously belonged to the American Federation of Labor (AFL).
The main dispute was between skilled and unskilled workers' membership in unions. The AFL did not want to cover unskilled workers in their union, but it changed policies and began enrolling them once the CIO was a rival. The CIO organized heavy industry, especially coal, autos, steel and rubber. The CIO and AFL set up rival unions in the garment trades, and for electrical workers and meatpackers. The CIO and AFL fought bitterly in the late 1930s for control of disputed industries. Both grew very rapidly during World War II, and both supported the New Deal Coalition of Franklin D. Roosevelt and Harry S. Truman. After Lewis quit in 1940 Sidney Hillman became the most powerful CIO leader.
Lewis and Hillman disagreed with the strategy of Samuel Gompers the AFL to concentrate on skilled workers. They He believed in "industrial unionism", which involved unionizing all he workers in an industry of all skill levels. Hillman was quite successful with this approach to clothing workers; John L. Lewis was developing a similar approach at the same time regarding coal miners. Hillman and Lewis, however, had a deeper strategy. They saw that industries like the needle trades (sewing clothing) and coal mining were dominated by hundreds of small firms, that engaged in ruinous competition. Wage comprised most of the cost of doing business in the needle trades and coal mining, so brutal competition meant lower wages. The way to improve conditions, raise wages and raise profits was to have the union control the industry by setting high wages. In a competitive marketplace, other firms were helpless when a competitor cut prices—they had to follow. But if the union policed the industry and prevented wage cuts and thus price cuts, then cutthroat competition with low wages and low wages would be impossible. The solution only worked in a few industries (especially clothing and coal) where conditions were exactly right (many small companies, wages the biggest expense.) These conditions did not apply in most industries. The problem in the 1920s was that unions were too weak to police their industries, so when the New Deal arrived in 1933, Hillman jumped at the chance to have the NRA police the industries and keep wages high. When NRA ended in 1935, Hillman helped Congress pass the Wagner Act which greatly facilitated union membership drives.
By 1935 membership in labor unions had sunk to a low figure as a result of unemployment. There were men around President Franklin Roosevelt who saw the tremendous possibilities of organizing labor as a political force. FDR was urged to promote this idea as the starting point in building up a powerful political labor movement. Lewis and Hillman threw their unions behind a new venture, the CIO (at first named the "Committee for Industrial Organization") with the dream of industrial unionization for all of America. Both the CIO and AFL unions strongly supported Roosevelt's landslide reelection in 1936, with Hillman heading the CIO campaign committee. The AFL in 1937 expelled the CIO (now renamed the "Congress of Industrial Organizations"), and the two federations spent much of 1937-40 fighting each other for membership in industries such as meatpacking and electrical equipment. Both grew rapidly.
Lewis was interested in bringing into existence industrial unions like his own, in which he had always believed. Roosevelt was interested in bringing into American labor unions as many voters as possible and in capturing their leadership to build a powerful labor faction which could control the Democratic party and which he and his allies could control through the vast power of the government and the vast powers of labor leaders, along with the immense financial resources that so great a labor movement would have. The Communists were interested in getting into key positions as union officers, statisticians, economists, etc., in order to utilize the apparatus of the unions to promote the cause of revolution. By the early part of 1938, over three million workers had been organized.
In 1940 Lewis broke with Roosevelt over foreign policy and Hillman became FDR's chief labor spokesman. CIO members, listening to Hillman not Lewis, voted 85% for FDR in 1940. In 1940-42 as the nation rearmed rapidly, Hillman handled labor affairs for the government, which involved rapid expansion of munitions industries and unionization of the new workers. Both the CIO and AFL grew very rapidly during the war, and they held their gains afterwards.
The CIO never set up a third party. Instead its goal was to dominate the Democratic party and use it to carry out a broad plan of liberal activism. Led by idealists such as Auto Workers' Walter Reuther and C.I.O. Secretary Jim Carey, CIO leaders by 1944 doubted that business could provide full employment after the war. Fearing a return to depression, they argue that more Government initiative was needed. PAC's 1944 platform contained specific demands for a planned economy, federally controlled—including everything from raising the standard of living in backward nations by granting them large credits, to free hot lunches for the 20,000,000 U.S. school children. In the event the conservatives came to power and rejected all such proposals.
Lewis and Hillman were never Communist Party members, and Lewis battled to prevent Communist infiltration of his union. The Comintern directed Lee Pressman  of the Ware group to assume the position of general counsel where he became known as "Comrade Big." The year 1936 was a period of furious organizing work by it among the unskilled workers of the country. As Lewis, David Dubinsky, and Hillman set about organizing millions of workers they were immediately up against the problem of finding skilled organizers to promote and manage the new unions.
There had been in the United States a Communist labor organization known as the Trade Union Unity League which took its instructions directly from Moscow. It is estimated that ten or fifteen thousand Communists were in these unions. In 1934, Moscow directed the Communist party in the United States to dissolve the Trade Union Unity League unions and to march the members of those unions into the American Federation of Labor. The purpose was not to advance the cause of labor unions or to get better working conditions for the members, but to use the apparatus of the labor union as an instrument of revolution. The Communist leaders saw in the rise of the CIO a better opportunity for their own revolutionary objectives than in the AFL and instructed their members to withdraw from the AFL and go into the CIO where they achieved disproportionate influence.
The rapid growth of the CIO, 1935–40, depended on the energies of Communists, at a time when the Communist party promoted a "united front" of all left-wing elements. CIO leaders welcomed Communists and fellow travelers (people who supported Communist objectives) but did not become party members such as Michael Quill, Joseph Curran, Harry Bridges, Ben Gold, Abram Flasner and numerous others.
Communists held about a third of the positions of power in the new CIO unions until they were purged in 1947-48. Walter Reuther of the autoworkers UAW was the most influential leader. Reuther helped purge the Communists and promoted an anti-Communist foreign policy as well as liberalism on economic issues. With the Reds gone, it became possible for the CIO to reunite with the AFL in 1955 to form the AFL-CIO, which remains the largest coalition of labor unions.
The AFL-CIO reached the peak of pits power in the 1950s. After 1970 it entered a steady, relentless decline in membership and influence that continues today. There are more retired members than active ones.
for a much more detailed guide see CIO Bibliography
- Bernstein, Irving. Turbulent Years: A History of the American Worker, 1933-1941 (1970), the best overview of the era
- Dubofsky, Melvyn and Warren Van Time John L. Lewis (1986).
- Fraser, Steve. Labor Will Rule: Sidney Hillman and the Rise of American Labor (1993). excerpt and text search
- Galenson, Walter. The CIO Challenge to the AFL: A History of the American Labor Movement, 1935-1941 (1960) online editiononline edition
- Lichtenstein, Nelson. Labor's War at Home: The CIO in World War II (2003)
- Millis, Harry A. and Royal E. Montgomery. Organized Labor (1945) online edition
- Zieger, Robert H. The CIO, 1935-1955 (1995) online edition, the standard scholarly history
- Communists and the CIO: From the Soviet archives, Harvey Klehr and John E. Haynes, Labor History, Volume 35, Issue 3 Summer 1994 , pages 442 - 446. 
- Turning Point?, Time magazine, Monday, Jul. 12, 1937.
- Communists in the miners union supported Russia and its ally Germany in 1940, and strenuously opposed FDR's efforts to help Britain fight Germany. Lewis went along with the Communists and attacked FDR.
- FBI Report, Underground Soviet Espionage (NKVD) in Agencies of the United States Government, October 21, 1946, United States Government, pgs. 298 - 300 pdf. "Leon Pressman, alias Lee Pressman, served as General Counsel for the Agricultural Adjustment Administration from 1933 to 1935; in 1935 he was appointed General Counsel for the Works Progress Administration. In 1937 he was appointed to the General Counsel for the National Congress of Industrial Organizations (CIO). Pressman was also associated with various Communist front organizations. Pressman was a known contact of Anatoly Gorsky, New York KGB Rezident, and Soviet Agents Alger Hiss and Harry Dexter White.
- FBI Silvermaster file, Vol. 132, pg. 109 pdf. "Pressman is said to have run arms to Spain during the Civil War via Mexico and to have worked with General Mark Moren in the project. Moren was involved in the Rubens Robinson passport case in 1938." See also Underground Espionage Agent, Adolf Berle notes, September 2, 1939. 
- 32,000 & Mrs. Rubens, Time magazine, Feb. 07, 1938. "In the first years of the Soviet Union, to escape from Russia was difficult and dangerous. Today it has become almost impossible, an attempt tantamount to suicide. Barbed and electrically charged wire, searchlight-equipped watch towers. 24-hour frontier patrols aided by bloodhounds and police dogs guard every mile of border. .... Weak from scurvy and dysentery, Konarski told correspondents: 'The camp contains about 32,000 prisoners. They are kept there until death results from hard work, bad food and consequent sickness. I met two American citizens in the camp, Arthur Hanley, a chemical engineer from California, and Edward Rose, a machinist from Boston, Mass. They said they came to Russia in 1921 as volunteer workers. Rose said he was arrested in Leningrad in 1923. Hanley was caught trying to escape from Russia to Latvia in 1925. Each was sentenced to ten years' imprisonment, but, although they have served out their sentences, they are still being held. They told me they know of three other native-born Americans who are held prisoner in other Soviet camps.'...Mrs. Ruth Marie Rubens (alias Robinson), one U. S. citizen officially known to be in jail in Moscow (TIME, Dec. 27 ). In Moscow on December 9 able, active U. S. Charge d'Affaires Loy W. Henderson learned that Mrs. Rubens had "disappeared"' from the big Hotel National next door to the U.S. Embassy. On January 18 the Soviet Foreign Office finally admitted that Mrs. Rubens was under arrest, failed to say on what charge.... hundreds of Germans are today in Soviet jails and for years German diplomatic & consular officials have not been allowed to see them."
- The Soviet World of American Communism, Harvey Klehr, John Earl Haynes, and Kyrill M. Anderson, Yale University Press, 1998, Document 13, pp. 58-68. ISBN 0-300-07150-7.
- Agitprop, By Eugene V. Dennis