During World War I (1914–18), the United States adopted laws designed to discourage dissent and punish any act that might interfere with the war effort. After the war's end, this repressive (domineering) climate continued. The main targets of the repressive efforts were various leftists, Socialists, labor organizers, Communists, and others, all lumped together in the public mind as "Reds."

Fueling the public fears were dramatic social changes after the war. The era saw strikes, race riots, and widespread political agitation, including bombings. One of the bombs, in June 1919, damaged the home of Attorney General A. Mitchell Palmer (1872–1936), who led what were known as the "Red Raids." Ignoring the U.S. Constitution, Palmer's agents arrested and detained many suspected "radicals." Some of these were recent Russian immigrants, and, in December 1919, Palmer ordered 249 of them deported to the Soviet Union. The climax of the Red Scare came in January...