Statement and Order by the President on Relieving General MacArthur of His Commands.
[1.] Statement by the President:
With deep regret I have concluded that General of the Army Douglas MacArthur is unable to give his wholehearted support to the policies of the United States Government and of the United Nations in matters pertaining to his official duties. In view of the specific responsibilities imposed upon me by the Constitution of the United States and the added responsibility which has been entrusted to me by the United Nations, I have decided that I must make a change of command in the Far East. I have, therefore, relieved General MacArthur of his commands and have designated Lt. Gen. Matthew B. Ridgway as his successor.
Full and vigorous debate on matters of national policy is a vital element in the constitutional system of our free democracy. It is fundamental, however, that military commanders must be governed by the policies and directives issued to them in the manner provided by our laws and Constitution. In time of crisis, this consideration is particularly compelling.
General MacArthur's place in history as one of our greatest commanders is fully established. The Nation owes him a debt of gratitude for the distinguished and exceptional service which he has rendered his country in posts of great responsibility. For that reason I repeat my regret at the necessity for the action I feel compelled to take in his case.
[2.] Order by the President to General MacArthur:
I deeply regret that it becomes my duty as President and Commander in Chief of the United States military forces to replace you as Supreme Commander, Allied Powers; Commander in Chief, United Nations Command; Commander in Chief, Far East; and Commanding General, U.S. Army, Far East.
You will turn over your commands, effective at once, to Lt. Gen. Matthew B. Ridgway. You are authorized to have issued such orders as are necessary to complete desired travel to such place as you select.
My reasons for your replacement will be made public concurrently with the delivery to you of the foregoing order, and are contained in the next following message. (See attached Statement by the President.)
Note: On April 11 the White House released the text of an order from Secretary of Defense George C. Marshall to Lt. Gen. Matthew B. Ridgway informing him that the President was appointing him to succeed Gen. Douglas MacArthur. He also notified General Ridgway that Lt. Gen. James A. Van Fleet would take his place as commander of the 8th Army in Korea.
On the same day the White House also made public the following:
1. A message, dated December 6, 1950, from the Joint Chiefs of Staff to General MacArthur. The message transmitted the text of a Presidential memorandum, dated December 5, directing that no speech, press release, or other public statement concerning foreign or military policy should be released until cleared by the State Department or the Department of Defense, and further directing that advance copies of speeches or press releases be submitted to the White House.
2. A message, dated March 20, 1951, from the Joint Chiefs of Staff to General MacArthur, informing him that the President was about to announce that the United Nations was prepared to discuss conditions of settlement in Korea.
3. A statement by General MacArthur, published in the New York Times of March 24, 1951, pointing out the weaknesses of Red China "even under inhibitions which now restrict activity of the United Nations forces and the corresponding military advantages which accrue to Red China." The statement also contained two paragraphs which are noted in Item 108  below.
4. A message, dated March 24, 1951, from the Joint Chiefs of Staff to General MacArthur informing him that the President had directed that his attention be called to the memorandum of December 6, 1950 (1 above), and further informing him that "in view of the information given you 20 March 1951 (2 above) any further statements by you must be coordinated as prescribed in the order of 6 December."
5. A letter to Representative Joseph W. Martin, Jr., House Minority Leader, dated March 20, 1951, which Representative Martin published in the Congressional Record of April 5 (vol. 97, P. 3380), and which spoke of "meeting force with maximum counter force" in the Korean conflict.
Harry S Truman, Statement and Order by the President on Relieving General MacArthur of His Commands. Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/230392