For nearly fifteen months President Abraham Lincoln tolerated undisguised resistance, incompetence, and clear insubordination from Major General George B. McClellan, commander of the Army of the Potomac and, for a few months, General-in-Chief of all Union armed forces. The President delayed his eventual decision to relieve McClellan from command for several reasons, including a misplaced respect and trust in McClellan's character and professionalism; his inability to find the right time and person for replacement; his nagging fear of both the Confederate potential and a McClellan inspired insurrection of Union forces; his political judgement; the lack of help he received from his senior advisors; and most important, his basic personal character, forever prone to tolerance and forgiveness. Considering the nature of the Civil War, Lincoln's delay probably cost the nation thousands of lives and huge property damage. This reality should serve to diminish historical accounts of Lincoln as a great, perhaps the greatest, war President in United States history. It seems clear, in retrospect, that President Lincoln should have acted quicker and more decisively in relieving General McClellan at the first hint that his senior General did not share and support his vision for conduct of the war.