In plain terms. The National Security Act of 1947 reorganized the U.S. military and intelligence establishment, creating the National Security Council, the Central Intelligence Agency, and a unified Department of Defense. It is the statutory foundation for the protection and classification of national security information, and for the intelligence-community framework that governs handling of classified and sensitive data.
Citation. Pub. L. 80-253 (Jul. 26, 1947); 50 U.S.C. ch. 44 (§ 3001 et seq.).