Sixty-four years ago this week President Harry S. Truman signed the National Security Act of 1947 into law. In a break with what had been previous American practice, this law set the stage for the establishment of the Department of Defense, the U.S. Air Force as a separate service, and the first publicly acknowledged peacetime intelligence agency, the CIA.
In effect, the National Security Act of 1947 marked America’s acceptance of the fact that it had become a Great Power and that it could no longer afford to turn its back on the world’s problems like it had after World War I.