General MacArthur's wish to expand the Korean War by deploying the army of General Chiang Kai-Shek and dropping no fewer than thirty (30) A-Bombs on various strategic targets located in both China and North Korea contrasted dramatically with President Truman's plans for a negotiated peace. Compounding the President's frustration was the fact that MacArthur seemed entirely unable to keep his yapper shut while in the company of reporters; during the previous December the White House had ordered MacArthur to clear all his remarks to the press with the President - which he failed to do. Truman found that MacArthur's crippling sense of self-grandeur and all-around general arrogance had become a major liability and he was absolutely delighted to fire him.
The General's dismissal on grounds of "insubordination" ignited the country in debate and inspired numerous municipalities throughout the country to rename streets and parks in MacArthur's honor.
A lengthier column on this topic can be read here...