Why did the US government adopt a more aggressive foreign policy in 1947?

The first 200 words of this essay...

The US adopted a more aggressive foreign policy in response of Britain telling it that it does not have enough money to protect Greece and Turkey from communism and wanted it to take its place in policing Europe.

Firstly, to bring in the context, the USSR had a sphere of influence and was taking over Eastern Europe. Truman was already worried about the expansion of the USSR/communism so he wanted to contain it. His containment plan was called the Truman Doctrine which marked the beginning of USA's changed attitude; it began in response of the Greece communist uprising. It was the first time the US had stepped in to back up the opponent of communism. So, they adopted this aggressive foreign policy here to contain the spread of communism from the East to the West of Europe, which meant that eventually communism would spread into USA.

The USSR found this offensive to them and they responded by setting up the COMINFORM to co-ordinate their satellite states and to make sure everything that happened in those states was by Stalin's commands.

To be able to "contain" the spread of communism, which USA believed succeeded when people faced