What happened
President Harry S. Truman asked Congress to support Greece and Turkey against perceived communist pressure, framing the request in broad ideological and geopolitical terms.
Why it matters
This is one of the clearest starting points of the Cold War as a structured American strategy. It helped move postwar rivalry from improvised tension into a durable doctrine of containment.
Notes
Use this as the opening Cold War policy anchor rather than treating the transition from wartime alliance as a single date.