President Truman signs the National Security Act

On July 26, 1947, President Truman signed the National Security Act (1947), establishing the Department of Defense, the CIA, the National Security Council, and the Joint Chiefs of Staff. From the article:

"President Truman signs the National Security Act
President Harry S. Truman signs the National Security Act, which becomes one of the most important pieces of Cold War legislation. The act established much of the bureaucratic framework for foreign policymaking for the next 40-plus years of the Cold War.

By July 1947, the Cold War was in full swing. The United States and the Soviet Union, once allies during World War II, now faced off as ideological enemies. In the preceding months, the administration of President Truman had argued for, and secured, military and economic aid to Greece and Turkey to assist in their struggles against communist insurgents. In addition, the Marshall Plan, which called for billions of dollars in U.S. aid to help rebuild war-torn Western Europe and strengthen it against possible communist aggression, had also taken shape. As the magnitude of the Cold War increased, however, so too did the need for a more efficient and manageable foreign policymaking bureaucracy in the United States. The National Security Act was the solution.

The National Security Act had three main parts. First, it streamlined and unified the nation’s military establishment by bringing together the Navy Department and War Department and establishing the Department of the Air Force all under a new Department of Defense. The DoD would facilitate control and utilization of the nation’s growing military. Second, the act established the National Security Council (NSC). Based in the White House, the NSC was supposed to serve as a coordinating agency, sifting through the increasing flow of diplomatic and intelligence information in order to provide the president with brief but detailed reports. Finally, the act set up the Central Intelligence Agency (CIA). The CIA replaced the Central Intelligence Group, which had been established in 1946 to coordinate the intelligence-gathering activities of the various military branches and the Department of State. The CIA, however, was to be much more–it was a separate agency, designed not only to gather intelligence but also to carry out covert operations in foreign nations.

The National Security Act formally took effect in September 1947. Since that time, the Department of Defense, NSC, Air Force and CIA have grown steadily in terms of size, budgets, and power. The Department of Defense, housed in the Pentagon, controls a budget that many Third World nations would envy. The NSC rapidly became not simply an information organizing agency, but one that was active in the formation of foreign policy. The CIA also grew in power over the course of the Cold War, becoming involved in numerous covert operations. Most notable of these was the failed Bay of Pigs operation of 1961, in which Cuban refugees, trained and armed by the CIA, were unleashed against the communist regime of Fidel Castro. The mission was a disaster, with most of the attackers either killed or captured in a short time. Though it had both successes and failures, the National Security Act indicated just how seriously the U.S. government took the Cold War threat."