The investigating committees sent their own stream of prisoners to jail — witnesses whose offense was refusing to inform. The board of the Joint Anti-Fascist Refugee Committee, including Dr. Edward Barsky and the novelist Howard Fast, served three-month to six-month terms in 1950 for refusing to surrender the names of donors who had aided refugees from Franco's Spain. Screenwriters, professors, union officers, and clergy followed, as HUAC perfected the exposure hearing: the point was not legislation but the ritual demand for names, with prison for those who stood on the First Amendment rather than the Fifth.

The last of the committee's prisoners came at the era's end: Carl Braden, the Louisville civil-rights activist, and Frank Wilkinson, organizer of the campaign to abolish HUAC itself, each served nine months to a year after the Supreme Court upheld their convictions 5–4 in 1961, and Willard Uphaus, a sixty-nine-year-old pacifist educator, spent a year in a New Hampshire jail for refusing to name his summer camp's guests. Their cases — and the national defense campaigns around them — helped turn public opinion against the committees, which lost their power in the following decade.