Final answer:
The Truman Doctrine was a U.S. policy established to provide military and economic aid to countries threatened by communism, starting with Greece and Turkey in 1947.
Step-by-step explanation:
The policy in question is the Truman Doctrine, which was a pivotal part of U.S. foreign policy during the early stages of the Cold War. On March 12, 1947, President Truman appealed to Congress for aid to support Greece and Turkey against communist pressures, arguing the United States had a duty to oppose totalitarian regimes. This aid included $400 million in military and economic assistance, which helped to keep Greece and Turkey from communist takeovers, reinforcing U.S. policy of containment.