Law Dictionary

Internal Security Act of 1950

Law popularly McCarran Act, 50 U.S.C. § 781 , repealed by 107 Stat. 2329 (1950)

legal Definition of Internal Security Act of 1950

required the registration of communist organizations in the United States and established the Subversive Activities Control Board to investigate persons thought to be engaged in “un-American” activities. It was a key institution in the era of the Cold War, tightening alien exclusion and deportation laws and allowing for the detention of dangerous, disloyal, or subversive persons in times of war or “internal security emergency.” Most of its provisions were later declared unconstitutional.

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