c) Truman Doctrine

The Truman Doctrine, initiated in 1947, represented a fundamental shift in American foreign policy. It was articulated by President Harry S. Truman in response to the crises in Greece and Turkey, where communist insurgencies threatened to overthrow democratic governments. This policy marked the start of America’s commitment to contain the spread of communism globally, transitioning from its traditional isolationism to a more active role in world affairs. The doctrine set the stage for the Marshall Plan and the establishment of NATO, playing a key role in the Cold War dynamics that defined global politics in the latter half of the 20th century.