The largest and most important revolutionary socialist organization in US history, the Communist Party USA was always a minority influence. It reached considerable size and influence, however, during the Great Depression and World War II years when it followed the more open line associated with the term “Popular Front.” In these years communists were much more flexible in their strategies and relations with other groups, though the party remained a hierarchical vanguard organization. It grew from a largely isolated sect dominated by unskilled and unemployed immigrant men in the 1920s to a socially diverse movement of nearly 100,000 based heavily on American born men and women from the working and professional classes by the late 1930s and during World War II, exerting considerable influence in the labor movement and American cultural life. In these years, the Communist Party helped to build the industrial union movement, advanced the cause of African American civil rights, and laid the foundation for the postwar feminist movement. But the party was always prone to abrupt changes in line and vulnerable to attack as a sinister outside force because of its close adherence to Soviet policies and goals. Several factors contributed to its catastrophic decline in the 1950s: the increasingly antagonistic Cold War struggle between the Soviet Union and the United States; an unprecedented attack from employers and government at various levels—criminal cases and imprisonment, deportation, and blacklisting; and within the party itself, a turn back toward a more dogmatic version of Marxism-Leninism and a heightened atmosphere of factional conflict and purges.
