Passage Several key sections of the Act were taken from the earlier
Mundt–Ferguson Communist Registration Bill, which Congress had failed to pass. It included language that Sen.
Mundt had introduced several times before without success aimed at punishing federal employees for passing information "classified by the President (or by the head of any such department, agency, or corporation with the approval of the President) as affecting the security of the United States" to "any representative of a foreign government or to any officer or member of a Communist organization". He told a Senate hearing that it was a response to what the
House Un-American Activities Committee (HUAC) had learned when investigating "the so-called
pumpkin papers case, the espionage activities in the
Chambers-
Hiss case, the
Bentley case, and others." President Harry Truman
vetoed it on September 22, 1950, and sent Congress a lengthy veto message in which he criticized specific provisions as "the greatest danger to freedom of speech, press, and assembly since the
Alien and Sedition Laws of 1798," a "mockery of the Bill of Rights" and a "long step toward totalitarianism". The House overrode the veto without debate by a vote of 286–48 the same day. The Senate overrode his veto the next day after "a twenty-two hour continuous battle" by a vote of 57–10. Thirty-one Republicans and 26 Democrats voted in favor, while five members of each party opposed it. Democratic Senator
Hubert Humphrey led the outnumbered opposition in the Senate despite having voted in favor of the law the first time.
Amended Part of the Act was repealed by the
Non-Detention Act of 1971 after facing public opposition, notably from Japanese Americans. President
Richard Nixon, while signing the repeal bill, referred to the internment of Japanese-Americans during World War II for historical context as to why the bill needed to be repealed. For example, violation of (Section 21 of "the Internal Security Act of 1950"), which concerns security of military bases and other sensitive installations, may be punishable by a prison term of up to one year. The part of the act codified as has been repealed in its entirety for violating the First Amendment.
Abolition The Subversive Activities Control Board was abolished by Congress in 1972. ==Constitutionality==