Yates v. United States (1957) was one of the last cases involving the
prosecution of American Communists and ruled that that the First Amendment
protects advocacy of ideas.
Communist Organizations and Freedom of Association
The Supreme Court developed several First Amendment doctrines in cases growing out of conflict between various members of the Communist Party and federal and state officials.
Congress adopted several statutes aimed at or applicable to communists, including the Alien Registration Act, or Smith Act, of 1940; the Internal Security Act, or McCarran Internal Security Act of 1950, also known as the Subversive Activities Control Act; and the Communist Control Act of 1954.
States also adopted criminal anarchy or criminal syndicalism laws aimed at communists, particularly during and after World War I — when communists gained control of Russia in 1917, and after which they often maintained ties to the American Communist Party — and in the 1940s and 1950s during the red scare. Such statutes included loyalty oaths and registration requirements, which led to several First Amendment challenges before the Supreme Court.
Following are Supreme Court cases involving those laws.