The House Un-American Activities Committee was formed in 1947 to investigate the supposed inclusion of Communist propaganda by Hollywood ("unamerican activities"). This led to the blacklisting of a number of filmmakers known as the "Hollywood Ten" after such, subsequently largely discredited, accusations were made against them. By 1951 the Committee's hearings were largely under the control of Republican Senator Joseph McCarthy. To many at the time the investigations seemed to have lost their original aim, and had taken on the aspect of a "witch hunt", due to the Senator's demands that witnesses "name names" of those sympathetic to the Communists.
At McCarthy's instigation the remit were widened to investigate the U.S. Army. In a now famous cross examination at these latter hearings, McCarthy's motives were publically discredited by an Army lawyer. Shortly afterwards, in 1954, the Senate censured McCarthy for "conduct contrary to Senatorial tradition".