The War’s Worst Day
Looking back at Antietam
Sep 24, 2012, Vol. 18, No. 02 • By GEOFFREY NORMAN
Then, on September 13, there occurred a small, accidental event that yielded absurdly consequential results, the proportions of which were Shakespearean. A couple of Union soldiers, resting in a field recently occupied by Confederate soldiers found an envelope containing three cigars wrapped inside a sheet of paper.
There was writing on the paper, and the soldiers read it. (One wonders how history might have gone differently if those soldiers had not been literate.)
The paper turned out to be an order from Lee’s headquarters, addressed to his widely dispersed commands, detailing his operational plans. It was dated September 9.
What has become known as “the Lost Order,” burned off the fog of war so completely that McClellan knew, in perfect clarity, the exact positions of his enemy’s forces and the intentions of their commander. In his headquarters, he held the Lost Order in front of one of his generals and said, “Here is a paper with which if I cannot whip Bobbie Lee, I shall be willing to go home.”
There was nothing mysterious about what needed to be done. At this time, Lee’s forces were on the western side of South Mountain. McClellan was to the east. The mountain runs north and south. To get at Lee before he could unite his divided army, McClellan would need to move his men through two passes in South Mountain and position them between Lee’s widely separated wings. In his order to one of his commands, McClellan wrote, “My general idea is to cut the enemy in two and beat him in detail.”
Lee had done the dividing for him. It remained for McClellan to move and exploit the opportunity. Yet, as always, McClellan and his subordinates acted without urgency. There were several hours of daylight left that day. The troops could have been put in motion immediately. And if that was not feasible, then they could have been pressed into a night march. But none of McClellan’s formations was on the move until the next morning, a loss of some 18 hours.
By then, Lee had learned from an informer of increased activity around McClellan’s headquarters and had moved to strengthen his defenses at Turner’s Gap and Crampton’s Gap in South Mountain. He did not have the numbers to hold the gaps when the Union forces did attack; they were too strong and determined. If Lee had thought them “demoralized” by their recent defeats, Union soldiers established otherwise. He may have had their general’s number, but he had woefully underestimated them.
The attack on Turner’s Gap—the day’s larger movement—was a tough fight with heavy casualties on both sides, including Union general Jesse Reno. The final assault that carried the pass was the work of General John Gibbon’s Black Hats, who became the Iron Brigade that day when McClellan, watching the assault, called them the best soldiers in his army and said, “They must be made of iron.”
The Confederate units defending the pass retreated, leaving the dead and many of their wounded behind. McClellan’s troops were through and in position to take on and overwhelm Lee’s scattered formations. It had taken far too long, but McClellan now had the initiative, while Lee was thinking retreat and the preservation of his army.
Lee’s message to the commander of one of his detached divisions began, “The day has gone against us and this army will go to Sharpsburg to cross the river.” The troops falling back on Sharpsburg numbered about 15,000, and Lee might have gone on retreating, across the river to safety, if he had not received word that Stonewall Jackson had taken Harper’s Ferry and could now rejoin Lee, who believed a hard march might accomplish this before McClellan acted.
McClellan, meanwhile, moved ponderously, spending hours studying Lee’s thin lines on the opposite side of Antietam Creek. On the 16th of September, as McClellan positioned his men and planned for battle, the scattered elements of Lee’s army arrived exhausted but ready to take a place in the line and fight.
It was increasingly clear that the advantage dropped into McClellan’s lap by the discovery of the Lost Order had been frittered away. McClellan had won a battle—South Mountain—but he had not destroyed Lee’s army and won the war.
But Lee was confident, and his subordinates, who saw him on the day before the battle, remarked on his serenity. McClellan seemed confident, too, leading his staff on a two-mile ride, along his line, exposed most of the way to Confederate cannon fire.
For the troops, the night of the 16th was remembered—by those who lived to remember it—as wet with intermittent rain and noisy with occasional rifle and cannon fire as troops took alarm at imagined shapes and movement and the sounds of distant and unseen riders. One green federal regiment—the 16th Connecticut, less than a month in service—panicked briefly when one soldier accidentally fired his rifle.
If it was a night for nerves, the morning was about slaughter. It began early on Lee’s left. McClellan had chosen to attack here because it allowed him to use a bridge across Antietam Creek that was screened from the Confederates as two others, nearer Lee’s center and right, were not. He used this bridge to move almost two thirds of his men into position for an early morning attack.
General Joseph Hooker’s corps opened the action and its objective was the high ground marked by a little church that belonged to the Dunkers—a sect whose belief in austerity and simplicity included a rejection of church steeples as an expression of vanity. The plain church was Hooker’s objective. He needed to clear a cornfield and two stands of hardwood to get to it.
Union troops launched a brutal, frontal assault, supported by artillery pieces firing grape and canister that left, Hooker said, “every stalk of corn in the northern and greater part of the field . . . cut as closely as could have been done with a knife.” And many Confederate soldiers torn to pieces, as well.
The assault surged on, driving the surviving Confederates until it seemed the church was within the Union soldiers’ grasp. But they were stopped by a counterattack; pushed back through the cornfield. Hooker had taken 2,500 casualties in two hours. On retiring he ordered another attack, this one by General Joseph Mansfield’s corps, on his left. This attack also aimed to take the high ground around the Dunker church and roll up Lee’s line. During a confused launch, Mansfield thought that some of his men, on the attack, were firing into some of Hooker’s who were retreating. Shortly after he realized that his troops were actually firing on the enemy, Mansfield was shot in the stomach. He died a little later, in an aid station.
The attack went on without him. Union troops made it through the cornfield and almost all the way to the Dunker church before they were stopped by troops Lee had moved over from his right. But the Union soldiers held their ground, and it looked as though one last push would take the objective and win the battle. This push was to come from General Edwin Sumner’s corps, the largest in the army. Certainly it had the weight. But the men were handled badly and exposed a flank to Confederate troops that had just made it to the field after a march from Harper’s Ferry. Their counterattack cut Sumner’s formations to pieces and ended any chance of a Union victory at this end of the line. The casualty count in the three attacking Union corps came to some 7,000 men, including Hooker, shot in the foot.
They had come close. Very close. It was a day of close calls.
Confederate casualties were also appalling. But they had held the left end of their line, and after the fighting died down, Stonewall Jackson sat on his horse eating a peach, listening as his staff surgeon reported on the casualties, and wondered if the next attack might not succeed.
Jackson shook his head and said, “Dr. McGuire, they have done their worst.”
This was another moment, another situation, that presented incomparable opportunity. Lee had no reserves to send to this portion of the battlefield. He was heavily outnumbered and no longer held a naturally defensible position. Some of the few troops he had—not more than 200—made a desperate counterattack, which stopped the Union momentum. Still, one more push...
There were troops to make it—a fresh corps under the command of General William Franklin with more than 8,000 men. But General Sumner’s corps had now taken more than 5,000 casualties in the fighting, and the old general (he was 65) had seen and had enough, even though McClellan in a rare show of offensive spirit had sent a message to both generals suggesting an attack.
“Go back, young man, and tell General McClellan I have no command! Tell him my command, Bank’s command, and Hooker’s command are all cut up and demoralized. Tell him General Franklin has the only organized command on this part of the field.”
It was the sort of thing McClellan did not have to hear twice. But it did not seem to occur to him, or to Sumner, that their enemy might be in even more desperate condition, which it was, with the center of the Confederate line so thinly held that the general in command later said something to the effect that only a miracle could account for its holding. The troops he would have needed to properly hold that line were sprawled dead in the Bloody Lane where Alexander Gardner would later photograph them. The grainy black and whites were exhibited in Mathew Brady’s studio in New York in the weeks after the battle.
With both sides fought out and bled to exhaustion on the north end of the line and in its center, McClellan was left with one last opportunity. General Ambrose Burnside’s corps was on the Union left, where a bridge of 125 feet crossed Antietam Creek. A high bluff overlooked the bridge from the other side of the creek, and it was held by the Confederates, but weakly. Lee had been taking men from this section of his line in order to hold off disaster elsewhere. But the few hundred men who were left had been enough to hold the bridge for the entire morning.
McClellan had sent couriers urging Burnside to move across Antietam Creek, finally provoking the general. “McClellan appears to think I am not trying my best to carry this bridge. You are the third or fourth one who has been to me this morning with similar orders.”
The bridge, of course, was not really the point. It was merely a way to get across the creek, and, once across the creek, to roll up the weak Confederate right and take the one ford across the Potomac. This would guarantee the destruction of Lee’s army. And it was possible here. Burnside, with 14,000 men, had the numbers, and Lee had no reserves. But first...the bridge.
After the war, the case against Burnside—who went on to other, even greater, military debacles—grew until it became part of the indictment against him that he never even needed to take the bridge. That the creek was shallow enough that his men could have waded it without wetting their belt buckles. More recent research seems to establish that this was not the case. What one thinks, looking down on the bridge from the bluffs that were held by Georgia sharpshooters that day, is that an able commander would have found a way across that little creek in less than the half day it took Burnside.
But he did take the bridge, finally, in the afternoon. And once he had troops across, he halted them and, since they were out of ammunition, brought up another, fresh formation rather than a resupply of powder and balls. And finally, in the late afternoon, when all was ready, he attacked.
The Union troops were on the verge of carrying the field, the day, and the war. Robert E. Lee looked on as his men retreated and broke for the safety of Sharpsburg. He looked out over the field and saw two distant formations.
And those, Lee asked, indicating the other formation.
“They are flying the Virginia and Confederate flags.”
“It is A.P. Hill up from Harper’s Ferry,” Lee said.
These were the last of his dispersed troops. They had marched 17 miles since daylight. Marched so hard that of 5,000 men who started, only 3,000 finished. But they attacked the Union flank, routing the unfortunate 16th Connecticut and driving Burnside’s men back to the bluffs he had spent so much time taking. Time given A. P. Hill to make his march.
It was victory enough, however, for Abraham Lincoln to issue the Emancipation Proclamation. Victory enough to persuade the Europeans to sit this one out. And insufficient enough that Lincoln relieved McClellan of command, this time with finality.
His replacement, however, was Burnside—with results that were not so much predictable as fated.
Geoffrey Norman, a writer in Vermont, is a frequent contributor to The Weekly Standard.