Communists represented a small, but significant, minority within the burgeoning labor movement of the late 1930s and early 1940s, especially within the unions of the Congress of Industrial Organizations (CIO), which arose after 1935 to rival the older and more conservative American Federation of Labor (AFL). Communists believed, as a matter of ideological conviction, that anti-capitalist revolution must begin with the working class; therefore, they threw themselves into the task of organizing workers into industrial unions with great enthusiasm.
Communists never comprised more than a tiny proportion of America's trade unionists, even within the CIO. But Communists did have a disproportionate impact. Several of the CIO's most militant and—for a time—successful unions had outright Communist leadership. These included the International Longshoremen's and Warehousemen's Union (ILWU), the International Woodworkers of America (IWA), and the United Electrical, Radio and Machine Workers of America (UE). Many other CIO unions, including some of the largest unions in the country—the United Auto Workers (UAW), United Steelworkers (USW), and United Mine Workers (UMW)—had non-Communist leaders but employed effective Communist organizers at lower levels within their organizations.
The CIO was never, as its critics frequently alleged, a mere front for Communist Party agitation. But the CIO did, for a long time, tolerate the presence of Communists within its ranks and benefit from Communists' commitment and organizing prowess.
Through the end of World War II, the CIO's model of Red-tolerant trade unionism was relatively successful. Between 1935 and 1945, millions and millions of American workers joined unions for the first time—both in the CIO and in the AFL, which began organizing aggressively to counter competition from the CIO. Unions raised wages, reduced work hours, and won improvements in working conditions. By 1945, more than 35% of the American workforce was unionized, and labor leaders hoped for a future in which unions shaped not only workplace conditions but also public policy and even business decision-making. (In 1946, the UAW attempted to introduce into its negotiations with General Motors not only an agreement on wages but also on the price GM would charge for cars.)
In retrospect, we can now see that the end of World War II marked not the beginning of a golden age for American labor but instead the beginning of the end. The proportion of American workers who belong to unions began to fall in 1946 and hasn't stopped; today, fewer than 12% of all workers—and fewer than 8% in the private sector—are union members.
The collapse of American labor began with the Taft-Hartley Labor-Management Relations Act, a piece of legislation that can only be understood in the context of the Cold War. Taft-Hartley, passed by a Republican Congress over President Truman's veto in 1947, used the threat of Communist subversion to justify rolling back many of the advantages labor had gained in the 1935 Wagner Act. Most of the bill's provisions—banning closed shops, secondary strikes, and the spending of dues for political purposes, while allowing states to pass union-busting "right to work" laws—had no Cold War purpose. They represented a long-stymied pro-business Republican agenda that had suffered under FDR's New Deal administration.
But these anti-labor provisions, which caused labor leaders and even Truman himself to denounce Taft-Hartley as a "slave-labor bill," were sold by Republicans as necessary to the national defense under the new conditions of the Cold War. The Communists tolerated within many unions were no longer mere radical agitators, but potential fifth columnists in the service of our new mortal enemy, the Soviet Union. Taft-Hartley targeted Communists within the labor movement by requiring union officers to sign affidavits affirming they were not members of the Communist Party. Any union that failed to sign the affidavits lost its right to a hearing before the National Labor Relations Board, and thus effectively lost any protection under federal law.
Taft-Hartley's anticommunist affidavits made it impossible for American unions to avoid a direct reckoning with the Communist problem, and that reckoning shattered the CIO. Several of the CIO's left-leaning unions, which rejected anticommunism as an illegitimate labor-splitting tactic, refused to sign the affidavits, threatening to undermine the CIO's legal status. In 1949 and 1950, the CIO responded by purging its Communists from its ranks, firing left-wing officials and expelling twelve unions that refused to abandon their Communist-tolerant ways.
The expulsions protected the CIO from charges that it threatened national security, but they also robbed the CIO of much of its original vitality. The expelled unions included some of the federation's most successful and militant—including the powerful ILWU and the UE, the third largest union in the entire CIO. The post-purge CIO lost the expansive sense of mission that had driven its rapid growth in the 1930s; the CIO after 1950 wasn't much different from the once-hated AFL. When the two organizations merged in 1955 to form the AFL-CIO, the new labor federation bore a much closer resemblance to the cautious old AFL than to the militant CIO of the Depression years. For more than 50 years now, the AFL-CIO has presided over the steady erosion of the American labor movement.
Taft-Hartley may not have been a "slave labor" law, but it certainly succeeded in its primary goal of weakening trade unionism in the United States. The Communist problem, immeasurably heightened by the emerging Cold War, made it impossible for American unions to continue their broadly successful Red-tolerant policies of the 1930s and early 1940s and provided the perfect wedge for conservatives to divide and conquer the labor movement.