On July 26, 1947, US President Harry S. Truman signs into law the National Security Act of 1947. The purpose of the act was restructure the military of the United States. Among the changes include in the act was to merge the existing Department of War and Department of the Navy into one entity, initially known as the National Military Establishment and later known as the Department of Defense. Furthermore, the National Security Act created the United States Air Force as a separate military branch, which had previously been part of the Army. The US Marine Corps was also preserved as an independent service under the Department of the Navy. Also, the National Security Council was established for the purpose of advising the President on issues of national security and foreign policy. Lastly, the act also created the Central Intelligence Agency (CIA) and thus the first peacetime US intelligence service.