During the 1930s, the dominant labor union in Hollywood, the International Alliance of Theatrical and Stage Employees Union (IATSE), was led by men with ties to organized crime. Studio heads also supported union leaders financially in order to inhibit strikes and keep labor cost increases low. After IATSE leaders were sentenced to prison terms for extortion, organizing drives by opposition labor groups began to surge. The Conference of Studio Unions (CSU), a craft union coalition headed by Herbert K. Sorrell, was founded in 1941 following a divisive, but successful strike against Walt Disney Productions by cartoonists aligned with Sorrell. During an eight-month CSU-led industry-wide strike in 1945, IATSE, aided by the Motion Picture Alliance for the Preservation of American Values (MPA), a right-wing anticommunist industry group, launched a campaign to brand their rival as communistic. A further strike marked by police violence occurred the following year, and in 1947, with the cooperation of Screen Actors' Guild president Ronald Reagan, the studio heads, MPA, and IATSE emerged victorious in the jurisdictional battle. In the following testimony before the House Committee on Un-American Activities (HUAC)—which the MPA had repeatedly urged to investigate subversives in the industry—Reagan and Disney portrayed the labor struggles solely in terms of a battle between forces for and against Communism.