From msnbc.com's Tom Curry
As commander in chief, the president has the right to remove a general from command “any time he sees fit,” said World War II general Omar Bradley. Dismissing an insubordinate, indiscreet, or incompetent general can sometimes provoke controversy.
Some notable cases:
Gen. George McClellan, 1862
President Lincoln repeatedly urged McClellan to pursue and attack Confederate forces. After the battle of Antietam, McClellan allowed the Confederate army to slip back into Virginia. “Are you not over-cautious when you assume that you cannot do what the enemy is constantly doing?” Lincoln asked McClellan in a letter a month before firing him in 1862. McClellan ran as the Democratic presidential candidate on a peace platform in the 1864 election, winning 45 percent of the popular vote, but only three states.
Chief of Naval Operations Admiral Louis E. Denfeld, 1949
Secretary of Defense Louis Johnson fired Denfeld, the Chief of Naval Operations and a member of the Joint Chiefs of Staff, after he told a House committee that the Navy was being dangerously weakened by decisions by Johnson and President Harry Truman that were uninformed and "arbitrary." Johnson had cancelled the building of a new aircraft carrier and wanted to emphasize strategic bombing instead of naval operations.
Gen. Douglas MacArthur, 1951
Commander of United Nation forces in Korea fighting the North Korea and Chinese armies, Gen. MacArthur defied Truman in 1951 by issuing a statement which scuttled cease-fire negotiations with the Chinese and criticizing Truman’s policies saying, “There is no substitute for victory.” Truman dismissed MacArthur, who returned to the United States to a hero’s welcome.
Maj. Gen. Robert L. Schweitzer, 1981
Schweitzer was fired from his White House job on President Ronald Reagan's National Security Council staff because he failed to get advance approval of a speech declaring that ''the Soviets are on the move, they are going to strike.'' Schweitzer also said the Soviets had gained nuclear superiority and the United States is ''in the greatest danger that the republic has ever faced since its founding days.''
Air Force Chief of Staff Gen. Michael Dugan, 1990
Defense Secretary Dick Cheney dismissed Dugan after he openly said that in the event of war with Iraq, the Air Force would bomb Baghdad and target Iraqi President Saddam Hussein, his family and his palace guard. Dugan’s comments came five weeks after Saddam’s armies invaded Kuwait. Cheney told reporters that Dugan's statements were "inappropriate" and showed "poor judgment at a sensitive time." Dugan was the first member of the Joint Chiefs of Staff to be dismissed since Denfeld in 1949.