The President and the general (George B. McClellan) provided strange contrasts. Each fought for a common goal, but the two could not get together. The President thought the general had "the slows". The general reciprocated, calling his Commander-in-Chief the "original gorilla". The difference between them--one of many-- was that the officer was expendable; the President was not. Without Lincoln the Union might well have been lost.
Abraham Lincoln did not, at first glance, appear to have the background or capacity to enable him to lead a nation through its greatest time of trial. Yet the ability was there in his will and character, the ability to mold the disparate people of the North into a single-minded willful body whose sole purpose was to win the war, and keep the Union together.
Even less apparent as Lincoln took office in 1861 was his instinctive grasp of the art of war. His lack of training and experience ultimately served to his advantage. Unencumbered by outdated military dogma, Lincoln effectively brought to bear his keen practical insight and common sense in the application of an overall strategic plan for the war and in the creation of a command system to carry it out.
Intuitively he sensed the military importance of a blockade of the southern ports, control of the Mississippi river, and the necessity to press the Confederacy on all sides at once. Most important of all, Lincoln had the foresight to keep up an unceasing search for the right man to lead his armies. The "slows" of George B. McClellan unfitted him for the task as did a series of other failings in a succession of other commanders, but Lincoln never stopped looking until he found the man, his general, his Grant.
The selection of Grant to lead the Union armies became the final link in the evolution of an effective unified chain of command. Secretary of War Stanton had responsibility for men and supplies; Chief-of-Staff General Halleck was the liaison with the military; General-in-Chief Grant directed all of the armies. And overseeing everything--combining statecraft and strategy planning--was Lincoln himself, the Commander-in-Chief.
Statesman, diplomat, strategist, and rallying point for the affections and loyalties of his people, Abraham Lincoln fought and won the Civil War more than anyone on the battlefield. it was his victory, his triumph for the Union, a reunited nation that, sadly, he would not live to see.