Why did truman believe greece needed american aid in 1947?

Truman believed Greece needed American aid in 1947 to prevent communism from growing in power in that nation. In a speech to Congress in March, 1947, Truman asserted that Greece was being "threatened by the terrorist activities of several thousand armed men, led by communists."

Truman also advocated intervention in Turkey, where the Soviet Union was seeking to gain control over the Dardenelles, the passageway for access from the Black Sea to the Mediterranean. Truman told Congress that "It must be the policy of the United States to support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures.”

Within the next months, Congress approved the President's request for $400 million in assistance for Greece and Turkey. This was the beginning of what became known as the "Truman Doctrine," Essentially, the Truman Doctrine pledged American support elsewhere in the world to check the spread of communist and Soviet influence.