The American Civil War lasted almost exactly four years, extending from the Confederacy’s firing on Fort Sumter in South Carolina on April 12, 1861 and ending with the South’s surrender on April 9, 1865. In between those dates were many bloody battles and enormous destruction of towns and countryside.

Why the Civil War lasted as long as it did is essentially an unanswerable question. History is replete with “what if?” moments and events, as war cannot be easily encapsulated in brief answers. Wars are not an abstraction; they are fought by human beings who are inherently fallible, and outcomes often hinge on imponderables such as weather or minute decisions regarding deployments of assets. If one wishes to understand why the Civil War lasted as long as it did, however, a good starting point could be President Abraham Lincoln’s exasperation with his commanding general, George McClellan.

Students of the Civil War are taught that an important advantage enjoyed by the Confederacy involved the number of skilled officers leading its army, led by General Robert E. Lee and including Generals Stonewall Jackson, J. E. B. Stuart, Nathan Bedford Forrest, and James Longstreet. These were, in fact, smart, capable leaders who did provide a marked advantage for the South. Facing them was General McClellan, Commander of the Army of the Potomac, with whom President Lincoln would prove to be enormously and infamously frustrated.

General McClellan was an extraordinarily cautious commander who, Lincoln believed, repeatedly failed to seize the initiative when it was available and repeatedly failed to capitalize on what successes he did enjoy. These frustrations were expressed by the president in his October 13, 1862 letter to General McClellan, the opening passage of which reads,

My dear Sir: You remember my speaking to you of what I called your over-cautiousness. Are you not over-cautious when you assume that you cannot do what the enemy is constantly doing? Should you not claim to be at least his equal in prowess, and act upon the claim? As I understand, you telegraphed General Halleck that you cannot subsist your army at Winchester unless the railroad from Harper's Ferry to that point be put in working order. But the enemy does now subsist his army at Winchester, at a distance nearly twice as great from railroad transportation as you would have to do without the railroad last named. He now wagons from Culpeper Court House, which is just about twice as far as you would have to do from Harper’s Ferry. He is certainly not more than half as well provided with wagons as you are. I certainly should be pleased for you to have the advantage of the railroad from Harper’s Ferry to Winchester, but it wastes all the remainder of autumn to give it to you, and in fact ignores the question of time, which cannot and must not be ignored.

This excerpt from President Lincoln’s letter was a precursor to his eventual firing of General McClellan and the latter’s replacement with General Ulysses S. Grant, whose temperament was decidedly less cautious than that of his predecessor. While McClellan had performed well in battles, his refusal to continue campaigns through to a more conclusive resolution could be considered a reason for the war’s prolongation. Whether this is fair can never be definitely determined, but there is reason to believe that Lincoln’s demands of a more forceful prosecution of the war than McClellan seemed willing or able to execute were well-founded.

That the war lasted as long as it did is more than a matter of concentrating on General McClellan’s shortcomings as a commander. The Confederacy represented a committed group of states united in their opposition to Lincoln’s determination to abolish slavery while preserving the Union. The Confederate Army was well led and fought bravely.

In the end, the North’s substantial advantages in material and wealth proved too difficult for the Confederacy to overcome. Southerners believed fervently that they were fighting to preserve a way of life, no matter that the Southern culture and economy remained contaminated by the crime of slavery. The South fought until it could do so no longer—an effort that required four long years to defeat.