National Security Act (1947)

National Security Act (1947)


In the aftermath of World War II, the United States government undertook a dramatic reorganization of the national military and intelligence community. Departments created for wartime operations, such as cryptology, intelligence, and domestic security, needed restructuring for useful peacetime employment. Congress, and a special council of presidential advisors, reviewed military and government operations. Based on their recommendations, the National Security Act of 1947 outlined the ambitious plan to unify the military departments under the direction of a cabinet-level secretary. The individual responsibilities of the army and navy were more clearly defined, and the air force was created. The National Security Act of 1947 created the National Security Council, a formal foreign policy and military advisory team for the president, and the Central Intelligence Agency (CIA). The act was amended several times between 1945 and 1985, yielding the current government, intelligence, and military structure present in the United States today.

Signed into law on July 26, the National Security Act of 1947 initiated an immediate reorganization of the intelligence community. During the war, the Office of Strategic Services (OSS) performed most intelligence operations and trained a new generation of intelligence personnel. Though the OSS was initially slated for dissolution after the war, advisors close to President Harry S. Truman convinced the president that the organization could be retooled for peacetime operation, especially as Cold War tensions with the Soviet Union mounted. The act thus established a civilian successor agency to the OSS, the Central Intelligence Agency (CIA). The CIA was granted a broader mission to collect foreign intelligence data and conduct strategic surveillance. The position of director of central intelligence was created to administer the new agency and serve as a liaison between the intelligence community and the executive branch. The act assigned the task of domestic intelligence to the Federal Bureau of Investigation (FBI).

To facilitate the sharing of information, the formation of strategic foreign policy, and the protection of national security, the National Security Act of 1947 established the National Security Council (NSC). Comprised of the president, vice president, secretary of state, and the secretary of defense, the council meets to discuss security, intelligence, and strategic issues. The director of central intelligence and the chairman of the Joint Chiefs of Staff serve on the NSC in an advisory capacity. The role of the council was intentionally left somewhat ambiguous in the act so that each president could use the council that best suited his administration and foreign policy agenda. The council mostly convened as an advisory board until the Nixon Administration when the NSC gained the permanence and prominence in foreign and strategic affairs that it has today.

The 1947 act substantially reordered the military, in addition to the intelligence community. The War Department was abolished, and its duties incorporated with those of the former Navy Department into the Department of Defense (DOD). The position of Secretary of Defense was created to govern the new Department of Defense, but the individual branches of military service retained their own Secretaries. The original National Security Act of 1947 has been amended several times to further alter the structure of the DOD. In 1949, the DOD was elevated to a high-level executive department and the secretary of defense gained more power over military department Secretaries. In 1986, the position of the secretary of defense was firmly established in the executive chain of command as part of revisions to national Continuity of Government plans.

The operational duties of the individual military branches were also altered by the adoption of the National Security Act. The organizational structure of the army remained the same, but new emphasis was placed on training and maintaining permanent, professional forces. The act granted the navy the ability to maintain airplane squadrons to conduct any flight operations that it deemed essential to its main sea operations. The navy also remained the governmental custodian of the marines. After the value of aircraft and air defenses were proved on the battlefields of Europe and in the Pacific Theater during World War II, the National Security Act of 1947 recognized the strategic need for a professional and permanent air fleet by creating the air force.

Amendments to the original 1947 act have changed some structural and functional aspects of the military and intelligence communities, but the basic structure remains in place today. The September 11 terrorist attacks on the United States sparked a reexamination of the structure of national intelligence services and the manor in which information is shared by government departments. The recent passage of the Homeland Security Act, and the creation of the Department of Homeland Security, signal the largest reorganization of government security and intelligence agencies since the National Security Act of 1947.



Hogan, Michael H. A Cross of Iron: Harry S. Truman and the Origins of the National Security State, 1945–1954. Cambridge University University Press, 1998.

U.S. Department of State. Foreign Relations of the United States: Department of State, 1945–1950. Washington, D.C., 1996.


CIA (United States Central Intelligence Agency)
CIA, Formation and History
FBI (United States Federal Bureau of Investigation)
National Security Advisor, United States
NSC (National Security Council)
NSC (National Security Council), History

User Contributions:

The above explanation of the national Security Council does not make any reference to the National Security Agency. Why? I understand that the technical intelligence capabilities of the United States were not totally adequate as conducted by the CIA. An exploitation of that fact would be in lighting. Additionally, there is no including of the NSC directives in the early 1950s that establish the intelligence collecting missions / abilities of the military services operating under the DIA, NSA or as part of the CIA!

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