In the middle of the 1950-53 Korean War, then U.S. President Harry Truman sacked Gen. Douglas MacArthur, saying military commanders must be governed by the policies and directives issued to them according to law, a recently declassified document showed Thursday.

When the Korean War broke out in 1950 with the communist North's invasion of the South, Truman quickly committed American forces to a combined United Nations military effort and named MacArthur commander of the U.N. forces.

But he fired MacArthur less than a year later, in April 1951, for failing to respect the president's authority after the general made remarks critical of Truman. Historians say that Truman was concerned about civilian control over the military.

"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," Truman said in a proposed statement declassified in April this year. "You will turn over your commands, effective at once, to Lt. Gen. Matthew B. Ridgway," he said.

In an additional statement, Truman said that he has reached a conclusion that "MacArthur is unable to give his wholehearted support to the policies of the United States Government." "Full and vigorous debate on matters of national security is a vital element in the constitutional system of our free democracy,"

Truman said. "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." Truman added that 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," Truman said. "For that reason, I repeat my regret at the necessity for the action I feel compelled to take in this case." (Yonhap)