Final answer:
President Truman removed General MacArthur from command due to his insubordination, public disagreements with presidential policy, and dangerous proposals to expand the war into China, potentially inciting a broader conflict. The Joint Chiefs of Staff supported the decision, which maintained the principle of civilian control over the military.
Step-by-step explanation:
President Truman removed General Douglas MacArthur from command during the Korean War due primarily to MacArthur's insubordinate actions and public disagreements with Truman's policy. MacArthur's insistence on expanding the conflict into China, including the use of nuclear weapons, was contrary to Truman's strategy of a limited war. Additionally, MacArthur's public questioning of presidential decisions and his unauthorized correspondence with political figures ultimately forced Truman to act to maintain civilian control of the military, which is a sacred principle in American governance. The Joint Chiefs of Staff supported Truman's decision, recognizing the potential danger of MacArthur's proposals, as they could have significantly escalated the conflict, potentially leading to World War III.
The aftermath of MacArthur's dismissal saw him receive a hero's welcome back in the United States, but Truman's actions were eventually seen as wise restraint when the full context of MacArthur's conduct and his deviation from authorized war plans were considered. While MacArthur's strategies might have broken the stalemate in Korea, they also risked broader conflict with China and the Soviet Union. The consensus was that expanding the war would have been a tragic error, and Truman's limited war policy was aimed at preventing further escalation.