keeping communism in its enclosed borders
President Truman worried what China might do if the war continued, but then MacAuther had told him that China would not intervene and he continued to push Northward.
Truman didn't want the U.S to enter into the major war that would involve huge numbers of troops and even atomic weapons Neither side won the Korean War, and the two Koreans remain divided till this day.
There are two things that did change: Truman had enlarged the power of presidency, and a new alliance called the Southeast Asia Treaty Organization (S.E.A.T.O). This alliance was formed to prevent the spread of communism. The Truman Doctrine had committed the U.S to aid the countries resisting communist aggression, and provided the first step toward what would become known as the Containment Policy.
President Truman established that the U.S would provide political, military and economic assistance to all democratic nations under threat from internal or external authoritarian forces. President Truman delivered a speech before a joint session on March 12, 1947, this is how The Truman Doctrine up-rose. The immediate cause for the speech was a recent announcement by the British Government that, as of March 31, it would no longer provide military and economic assistance to the Greek Government in its civil war against the Greek Communist Party.