<P> The Truman Doctrine was an American foreign policy whose stated purpose was to counter Soviet geopolitical expansion during the Cold War . It was first announced to Congress by President Harry S. Truman on March 12, 1947, and further developed on July 12, 1948, when he pledged to contain threats to Greece and Turkey . Direct American military force was usually not involved, but Congress appropriated financial aid to support the economies and militaries of Greece and Turkey . More generally, the Truman Doctrine implied American support for other nations allegedly threatened by Soviet communism . The Truman Doctrine became the foundation of American foreign policy, and led, in 1949, to the formation of NATO, a military alliance that is still in effect . Historians often use Truman's speech to date the start of the Cold War . </P> <P> Truman told Congress that "it must be the policy of the United States to support free people who are resisting attempted subjugation by armed minorities or by outside pressures ." Truman claims that because totalitarian regimes coerced free peoples, they automatically represented a threat to international peace and the national security of the United States . Truman made the plea in the midst of the Greek Civil War (1946--49). He argued that if Greece and Turkey did not receive the aid, they would inevitably fall to communism with grave consequences throughout the region . Because Turkey and Greece were historic rivals, it was considered necessary to help both equally even though the crisis in Greece was far more intense . </P>

What is the historical significance of the truman doctrine