Truman Doctrine (March 1947)

Britain told the U.S. it could no longer afford to support the Greek government against communist insurgents. President Truman responded with a speech to Congress that articulated a new American foreign policy: "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." Congress voted aid for Greece and Turkey. The Truman Doctrine made containment official American policy. It is the moment many historians mark as the official start of the Cold War.