Final answer:
The Truman Doctrine was a policy declared by President Truman stating that the United States would support nations resisting communist subjugation, particularly providing military aid to Greece and Turkey in the eastern Mediterranean.
Step-by-step explanation:
The anti-communist stance that President Truman adopted concerning the geopolitical tensions in the eastern Mediterranean is referred to as the Truman Doctrine. This policy declared that the United States would provide support to "free peoples who are resisting attempted subjugation by armed minorities or outside pressures." In the specific context of this Doctrine, the United States pledged to deliver military aid to Greece and Turkey to curb the spread of Communism, signifying a shift from the previous era of American isolationism to an assertive international role in containing Soviet influence.