From the 1930s through the 1950s, Congress intensively investigated alleged political radicals. The House Committee on Un-American Activities focused on universities, labor unions, and the film industry. In 1947 the committee called Hollywood actors, directors, producers, and screenwriters to testify regarding communist influence on motion pictures. Ten men who refused to state their political affiliations, claiming First Amendment rights, were imprisoned for contempt of Congress. The “Hollywood Ten” became the first victims of a blacklist by major movie studios that curtailed hundreds of careers before it ended in 1960.
The Chairman. Are you now, or have you ever been, a member of the Communist party? Mr. Trumbo. I believe I have the right to be confronted with any evidence which supports this question. I should like to see what you have.
House Un-American Activities Committee Hearing, October 28, 1947