Question

Explain how the Truman Doctrine differed from the foreign policy exercised by the United States between the two world wars.

Answer 1

One way that it was different is that it certainly wasn't isolationist -- the US was taught a harsh lesson in both world wars, that events elsewhere could affect it despite being thousands of miles away.

So, Truman's Doctrine of containment was a more pro-active approach to confronting potential threats to the United States. In this case, communism. To combat that threat, the US embarked on a policy of finding friends and allies throughout the world that it could count on to deflect the growing influence of the Soviet Union in a worldwide chess game. In the old days, the US would just stay content within its borders and try to ignore what was happening outside because of its strong isolationist stance.