McCarran Internal Security Act - Legislative History

Legislative History

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 a federal employee from 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."

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 as soon as it received the President's veto message on September 22. The Senate overrode his veto on September 23 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.