The US tried to fight communism in several different ways.
1) Truman Doctrine: This provided financial assistance to Greece and Turkey to ensure that they did not fall under communist influence. With this assistance, they would be able to stabilize their economy and the US would be able to influence their policies.
2) Marshall Plan: This was a financial package given to countries of Western Europe from the US. This included $13 billion dollars of aid so that these countries could establish a similar political and economic structure to that of the US. This plan was wildly successful.
3) House Un-American Activities Committee: This federal committee was focused on trying to find communists within the US borders. However, this would be considered extremely unsuccessful. Many civil liberties and constitutional rights were broken and many peoples careers were ruined even though many of them were not proven of any wrongdoing.