
"On 11 April 1951, US President Harry S. Truman relieved General of the Army Douglas MacArthur of his commands for making public statements that contradicted the administration's policies. MacArthur was a popular hero of World War II who was then the commander of United Nations forces fighting in the Korean War, and his relief remains a controversial topic in the field of civil-military relations."

"MacArthur led the Allied forces in the Southwest Pacific during World War II, and after the war was in charge of the Occupation of Japan. When North Korea invaded South Korea
in June 1950, starting the Korean War, he was designated commander of
the United Nations forces defending South Korea. He conceived and
executed the amphibious assault at Inchon
on 15 September 1950, for which he was hailed as a military genius.
However, when he followed up his victory with a full-scale invasion of
North Korea on Truman's orders, China intervened in the war and
inflicted a series of defeats, compelling him to withdraw from North
Korea. By April 1951, the military situation had stabilized, but
MacArthur's public statements became increasingly irritating to Truman,
and he relieved MacArthur of his commands. The Senate Armed Services Committee and the Senate Foreign Relations Committee
held a joint inquiry into the military situation and the circumstances
surrounding MacArthur's relief, and concluded that "the removal of
General MacArthur was within the constitutional powers of the President
but the circumstances were a shock to national pride."
Source: Wikipedia