Well, one thing you can say about every American president is if nothing else, they are all politicians. Politicians are noted for having the trait of eliminating any perceived threat to their power base. Douglas MacArthur was seen by Harry Truman as a threat to the White House. What Truman did was what any politician does, eliminates any threat to his power. It was common belief that when the war was over, MacArthur would likely make his own run for the presidency. In1951, the removal of MacArthur was very unpopular in America and still remains a debated issue to this day.
http://www.pbs.org/wgbh/amex/macarth...re/versus.html