Among its many terms, the McCarran Act required that the American Communist Party and any organization affiliated with it register with the U.S. attorney general. The bill also made it illegal to establish a totalitarian dictatorship or to conceal membership in a communist organization when applying for government employment or using a passport. In addition, the act stipulated that communists or other people deemed subversive or a danger to the public welfare could be detained or deported. Naturalized citizens who fell into the last category could face denaturalization and, ultimately, deportation. Finally, the legislation established the Subversive Activities Control Board, which was empowered to investigate any person suspected of engaging in un-American activities.
The implications of the act for civil liberties were obviously great. But this was just the beginning of the excesses of McCarthyism. In June 1952, McCarran and Senator Francis Walter introduced the McCarran-Walter Act, which imposed stricter regulations on immigration and tightened laws relating to the admission and deportation of "dangerous aliens" as defined by the Internal Security Act. In August 1954 Congress passed the Communist Control Act, which among other things stiffened the penalties against those who failed to register with the attorney general and deprived the Communist Party of due process of law. Over time and bit by bit, portions of the Internal Security Act were ruled unconstitutional by the U.S. Supreme Court. The act was entirely repealed by Congress in 1990.
Paul G. Pierpaoli Jr.
Ybarra, Mike. Washington Gone Crazy: Senator Pat McCarran and the Great American Communist Hunt. Hanover, NH: Steerforth, 2004.