By Jay Holmes
Last week we looked at the habitual bad intelligence that paved the road to the Battle of Antietam in the American Civil War in Paved with Bad Intelligence–The Road to Antietam. This week, we see how it was enough to negate an intelligence windfall.
Lee knew that McClellan was highly intelligent and skilled, but that he was also cautious by nature. Lee was also still hoping to inspire an uprising against the Union in Maryland, and he operated with the assumption that he could defeat McClellan by maneuvering more quickly than the Union Army. Then, for uncertain reasons, Lee violated a major rule of warfare. He divided his forces in the face of a superior enemy and sent Stonewall Jackson’s troops to capture weapons and supplies at Harper’s Ferry.
On the morning of September 13, Union troops of the 27th Indiana Infantry rested in a meadow outside of Frederick, Maryland. They serendipitously took their break at a site that had previously been the location of the General Lee’s headquarters.
At that site, Sergeant John Bloss and Corporal Barton Mitchell found a piece of paper wrapped around three cigars. Known as Lee’s “Lost Orders,” the paper was a message containing Lee’s detailed plan of battle, addressed to Confederate General D.H. Hill. The men quickly handed it over to their commander. The Indiana Division’s adjutant general, Samuel Pittman, recognized the handwriting in the message as belonging to his prewar friend Robert Chilton, now the adjutant general to Robert E. Lee.
Pittman delivered the message straightaway to General McClellan. McClellan boasted that, with the information he now had, he would gladly be willing to go home if he could not defeat Lee. This “boast” was in fact a hedged bet. If, with the intelligence windfall he had in hand, he could not produce a resounding victory, he should have gone somewhere less pleasant than “home.”
The new information wiped out Pinkerton’s terrible intelligence assessment. McClellan now knew that Lee’s army was dangerously divided into five sections and stretched out over a 35-mile area that was split by the Potomac River. McClellan was twelve miles from the nearest Confederate unit at South Mountain. He was in a position that all commanders dream of in their wildest drunken moments. In their sober moments, they never dare to hope for such generosity from the capricious gods of war.
McClellan, poised to become the great Napoleon-like general that he always knew he could be, did what Napoleon never would have done. He waited. Then he waited some more. His division commanders grew restless. Then they grew anguished. Elation fermented into quiet disgust. Finally, after eighteen hours, McClellan gave the order to move.
By now, much of Lee’s army was concentrated in favorable high ground near Antietam Creek. Lee had used the time granted him to send forces to plug the pass at South Mountain. His troops had set up defensive positions there and slowed McClellan’s advance.
The Union Army finally approached Lee’s Confederate Army on September 16. Stonewall Jackson’s troops had still not returned from Harper’s Ferry to Lee’s position, and Lee had less than 40,000 men, their backs to the Potomac.
McClellan’s 75,000 well-rested troops could have conducted a successful flanking maneuver against the Confederates. If McClellan had fallen off his horse or gotten drunk, they likely would have. Instead, McClellan allowed his uncertainty about the intelligence to confuse a clear and reasonable battle plan. McClellan delayed the attack until the following morning.
On the morning of September 17, Union Army General Joseph Hooker led the assault against the now well-entrenched Confederate forces. Rather than concentrating a reasonable portion of his forces against a single point of the Confederate line, McClellan allowed the battle plan to devolve into consecutive piecemeal attacks.
Confederate General Jackson and his troops finally arrived in time for Jackson to earn the nickname “Stonewall” for his defense of the Confederate flank. By the end of the day, both armies had suffered terrible casualties. The dead, wounded, or missing numbered 12,000 on the Union side and 10,000 on the Confederate side.
The balance of losses left McClellan with an even greater numerical advantage, in that a larger percentage of his army was still capable of battle. Over 25,000 of his army were fresh troops that had not yet been engaged.
Lee, on the other hand, had no fresh troops remaining. The Confederate lines had held, but they were overall in worse condition than the Union troops. McClellan could still have captured or killed Lee and his army.
With victory staring him in the face, rather than pressing his advantage, McClellan agreed to a truce for both sides to recover their wounded and bury their dead. When night fell, Lee thanked God and withdrew from the field as quickly and quietly as he and his army could. He salvaged enough of his forces to return to defend Virginia, preventing McClellan from having a straight shot through to Richmond. George McClellan had squandered a golden opportunity to deal a crippling blow to the Confederacy.
Lincoln was disappointed in McClellan’s performance, but, unlike McClellan, he knew how to seize an opportunity. The victory at Antietam Creek gave him public relations momentum. On September 22, Lincoln announced his Emancipation Proclamation.
The Proclamation would not take effect until January 1, 1863, and then, it was conditional. Only slaves in Confederate territory were freed. Slaves in the four Union slave states still remained in bondage. Since the Confederate States were not inclined to obey any Union proclamations, only around 40,000 slaves in captured territory were actually freed at the time of the Proclamation. However, the real impact of the bloodiest day in US history was that Lincoln was able to score a monumental diplomatic victory. After the victory at Antietam and the Emancipation Proclamation, no European nation was willing to support the Confederacy in a war to defend the institution of slavery.
Due to poor intelligence and the mishandling of intelligence, Lee miscalculated the sentiments of Maryland, and McClellan dawdled away a windfall opportunity. Lee allowed himself to anticipate a States’ Rights event in Maryland, and the false analysis that men would throw themselves in for the Confederates. His failed intelligence caused him to launch a campaign that he had little chance of winning. McClellan’s refusal to accept and act on the best intelligence kept him from completely crushing Lee’s army and marching on Richmond. Nearly three more years of bloody war remained to be fought, but the fate of the Confederacy was sealed. It was a case when a perfect intelligence windfall was defeated by habitual misuse of intelligence.