What foreign policy did the US adopt after the World War 2?

They adopted a policy of INTERVENTION, in Europe in contrast to their policy of isolation in the inter-war period. They intervened to stop the spread of Communism more specifically called CONTAINMENT. They tried to contain Communism in Russia, it slightly failed as it did spread to much of Eastern Europe however it did succeed on Western Europe and Greece. They did this by strengthening European economies with massive loans among other things.