A principle of US foreign policy aimed at containing communism. It was enunciated by President Truman in a message to Congress at a time when Greece and Turkey were in danger of a communist take‐over. Truman pledged that the USA would “support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures”. Congress voted large sums to provide military and economic aid to countries whose stability was threatened by communism. Seen by communists as an open declaration of the Cold War, it confirmed the awakening of the USA to a new global responsibility.