Containment & the Truman doctrine
Containment is a policy of stopping the enlargement of an enemy, or the ideals of the enemy. This came into play in the Cold War with the United States using it to stop the spread of communism. Although Uses of the policy of containment prior to the Cold War include the attempt to stop the Nazis in WWII, and the U.S. trying to contain Japanese imperialism from 1937-1941. These events did not use the term "containment," but they were examples of policies of containment.
The Truman Doctrine
President Harry Truman put into effect that the United States would support any nation who was anti-communist or under siege from a communist nation. The support could be military, economic, and/or political assistance. The Truman Doctrine was issued on March 12, 1947 in front of Congress in reply to the communist threats in Greece and Turkey after Great Britain stopped giving aid to those countries. President Truman wanted to stop any communist regime from growing and spreading its roots into other nations. Truman added that the United States needed to stop the communist party in Greece, to unsure stability in Turkey, and throughout the rest of the Middle East. He also added that international peace and stability, and therefore the security of the U.S., depended on the stopping of totalitarian and authoritarian regimes. Out of the Truman Doctrine came the National Security Act of 1947 which reorganized the military and foreign policy of the United States. The Central Intelligence Agency (CIA) was also formed out of the National Security Act. The Truman Doctrine paved the way for American containment of communism.
What the Truman Doctrine and the policy of containment showed the world was that the United States was willing to do almost anything to stop the spread of communism. For the U.S., the "iron curtain" had spread far enough, and it needed to be stopped. However, if the British had not pulled support from Greece and Turkey, the doctrine and policy would most likely have not come into play as much in the Cold War. This is because it was necessary for Greece and Turkey to be communism free for the security of the United States. The Truman Doctrine gave support to countries trying to escape the grasps of communism and attempted to stop it in its tracks.