What was America's new role after World War 2?

After the world war, USA immediately got engaged in cold war with Soviet Union. As a result USA played an important role in global politics, specially in Europe, South East Asia and Pacific. In a frenetic effort to control spread of communism USA engaged in a number of full scale and limited conflicts like Korean war and Vietnam War. USA also funded anti-communist conflicts like Afghanistan war against USSR. A lot of investment economical and political was done in many countries like Pakistan, Turkey, Iran etc.