The 1950-53 Korean War tested, as no other war prior or since, the U.S. military's subservience to civilian control. Ironically, President Harry Truman fired MacArthur for insubordination when the five-star general was the supreme commander of U.N. forces in Korea (88 percent of which were American).
The Truman-MacArthur dustup erupted over MacArthur's plan to destroy Yalu River bridges linking Communist China and North Korea. Truman, fearing an expanded war with China and/or the Soviet Union, overruled MacArthur. In October 1950, China did intervene. The war that seemed so close to being over became a bloody stalemate that eventually took the lives of 33,651 U.S. servicemen killed in action and 3,652 more who died from illness, accidents and other causes not directly related to battle.