The document discusses how after World War I and the Russian Revolution, "red scare" hysteria gripped America and anti-radicalism grew. This led Attorney General Palmer to round up suspected radicals in 1919-1920. Many states passed laws against advocating violence for social change. Conservatives used the red scare to break unions, claiming unions were communist. A resurgent Ku Klux Klan also spread nativist sentiment in the early 1920s before eventually declining.