The main purpose of the Truman Doctrine was to prevent the spread of communism.
On March 27, 1947, Harry Truman gave a speech known today as the Truman Doctrine. Within this speech, he talked about how he wanted to help countries like Greece and Turkey stop the spread of communism.
The United Kingdom did not want to help Greece and Turkey any further, as they had no money to spare after World War II, so Harry Truman decided that the United States would help them stop the spread of communism.
