One of the best books I have ever read on the Battle of Antietam is Unfurl Those Colors by Vince Armstrong. While the book focuses primarily on the actions of the Second Corps in the Maryland Campaign, it also provides a detailed description of the decision making process of George B. McClellan during that campaign. While this book does not provide a comparative exhaustive analysis like Joseph Harsh made of Lee’s actions in Maryland, it is nevertheless the most fair and unbiased account of George B. McClellan’s operational planning and battlefield decision-making that is currently available. Read it with the chapters on the Maryland Campaign found Ethan Rafuse’s McClellan’s War to get a good picture of McClellan’s operational designs. Hopefully the McClellan version of Taken at the Flood will be written some day.
In the process of reading the book, I added 269 new quotes to my database. As part of my collection regimen, I examine the footnotes that are attached to every quote. One of the references is the Report of the Joint Committee on the Conduct of the War - Part One - Army of the Potomac. Dominated by the Radical Republicans, the Joint Committee was originally comprised to examine the Union disaster at Balls Bluff but quickly expanded its charter to look into any and all battlefield operations of the Union Army where it could reap political capital. A favorite target of the Committee was the campaigns of General George McClellan.
If you are willing to work through it, there is some fascinating reading there. Beginning on page 359 is the particularly interesting testimony of Edwin Sumner. He had been called to testify on his entire tenure in the Army of the Potomac. Sumner’s testimony runs for twelve pages with the last three devoted to the Maryland Campaign. Sumner testified on February 18, 1862 in Washington DC. He was on his way to take command of the Department of Missouri.
Three committee members questioned Sumner. They were the committee chair, Ben Wade, (R-Ohio), and Congressmen John Covode (R-Pennsylvania), and Daniel Gooch (R-Massachusetts). There were other members on the committee including several Democrats but none of them apparently were present or asked any questions.
By the Chairman:
Question. Will you now go on and give us a brief and concise history of the Maryland campaign?
Answer: The day after we reached the Potomac I was ordered to place my command in camp at Tenallytown. I remained there three days, and was ordered then to advance. The following day General Banks s corps was added to my command. My command was on the extreme right of the army as it advanced. We were not engaged at South Mountain, but continued on until we reached Antietam. One division of my second corps, under Richardson, was drawn up within shelling distance of the enemy, and I lost some men there and one or two valuable officers. The second night after our arrival there I was informed that General Hooker had been ordered to advance towards the left of the enemy with his corps. In the evening I was ordered to send forward General Mansfield, with Banks s corps, to the support of Hooker, and to hold my own corps in readiness to march an hour before daylight. It was ready at that time, but I did not receive the order to advance until twenty minutes past seven o clock in the morning.
On going upon the field I found that General Hooker s corps had been dispersed and routed.[i] I passed him some distance in the rear, where he had been carried wounded, but I saw nothing of his corps at all as I was advancing with my command on the field. There were some troops lying down on the left which I took to belong to Mansfield’s command.[ii] In the meantime General Mansfield had been killed, and a portion of his corps (formerly Banks s) had also been thrown into confusion. Sedgwick’s division was led by myself on the right of Banks corps. We sustained a very heavy fire there for some time. The enemy made a very desperate attempt to turn our left, and the fire became so severe that even my right division faced from it and marched at least a third of a mile before I could stop them[iii]. They did not break, but marched off in columns from the fire. They were then halted and placed in a position which was held. My two other divisions, French s and Richardson s, drove the enemy a considerable distance and never retreated an inch. I have always believed[iv] that, instead of sending these troops into that action in driblets, as they were sent, if General McClellan had authorized me to march these 40,000 men on the left flank of the enemy, we could not have failed to throw them right back in front of the other divisions of our army on our left, Burnside’s, Franklin’s, and Porter’s corps; as it was, we went in, division after division, until even one of my own divisions was forced out. The other two drove the enemy and held their positions. My intention at the time was to have proceeded entirely on by their left and moved down, bringing them right in front of Burnside, Franklin, and Porter[v].
By Mr. Gooch:
Question. And all escape for the enemy would have been impossible?
Answer. I think so.
By the Chairman:
Question. Why was not that done?
Answer. I do not know; perhaps the general thought it was better to bring one corps at a time into action.
Question. How came our divisions to be forced back in that way; did they attack superior numbers?
Answer. At the points of attack the enemy was superior.[vi] General Hooker’s corps was dispersed; there is no question about that. I sent one of my own staff-officers to find where they were; and General Ricketts, the only officer we could find, said that he could not raise 300 men of the corps.
By Mr. Gooch:
Question. This was after General Hooker was wounded?
Answer. Yes, sir; he was some distance in the rear, having his wound dressed.
By Mr. Covode:
Answer. I supposed at the time that we were about equal at Antietam. I believe the enemy say otherwise; but it was my belief, from all that I could see and hear on the field, that there were about 80,000 men on each side there.[vii]
By the Chairman:
Question. Who were victorious in that battle?
Answer. We were. We held the ground upon which the battle was fought, and the enemy retreated.[viii]
Question. What was the reason we did not destroy that army after its defeat at Antietam?
Answer. It had been a very severe action uncommonly severe. My own corps lost something over 5,000 men that day in killed and wounded, and some of the other corps lost very nearly as much. Troops are not exactly prepared to make a rapid pursuit the next day after such a battle as that. And another reason was this, I believe, General McClellan knew that re-enforcements were on the march to him, being pushed up as rapidly as possible; and he knew, probably, that the enemy should receive no reinforcements; therefore he thought proper to pause a little after that severe battle before he pressed the enemy. There is a great deal to be done after an action of that kind. It takes a day or two to look about you a little, to collect the dead and wounded, and take care of them. Knowing that these re-enforcements were on the march from Washington, I thought it was prudent for the general to halt a little after that severe action until his re-enforcements came up.
Question. The enemy had a difficult river to cross, and there was no opposition to their crossing the river, I believe?
Answer. It was not very difficult for them to cross it. They could ford it in many places.
By Mr. Gooch:
Question. When did you first learn that the enemy were retreating, after that battle?
Answer. I believe it was the second night after the action.
Question. Were our forces in a condition to pursue, when you found that the enemy had commenced their retreat?
Answer. You mean before they got across the river?
Question. Yes, sir; as the information reached you that they had begun to retreat.
Answer. That is a difficult question to answer. With old regular troops, tried men, a night attack upon the enemy there would have been successful; but there is a great deal of risk in making night attacks with new troops.
By Mr. Covode:
Question. What prevented General Porter s corps from attacking the enemy?
Were they not in condition to attack?
Answer. I do not know about that. I know there was some disappointment on the part of General Burnside about it.[ix]
Question. Were they engaged in that fight at all?
Answer. I think not. I think they were held as reserves.
By the Chairman:
Question. There was a great deal of delay in pursuing the enemy after they had recrossed the river, and after you had received your re-enforcements. What caused that delay?
Answer. I do not know. A large army is a very unwieldy machine to move.
It takes a great deal of time to organize the means of transportation, procure supplies, &c. Scarcely any man can move 100,000 men without making very close calculations, and an inexperienced man cannot make those calculations. I do not know the reason for the delay, unless it may have been thought necessary to reorganize and refit the army; and whether that could have been done in less time or not I am not prepared to say.[x]
Question. What effect had the surrender of Harper s Ferry upon the battle of Antietam?
Answer. The 30,000 of the enemy who took Harper s Ferry came up to Antietam and took part in the action there.[xi]
Question. When the army moved from Washington in pursuit of Lee, in your opinion, what should have been our line of movement?
Answer. I think it would have been much better for our whole army to have gone right up to Harper s Ferry, on the south side of the Potomac, and left Pennsylvania to take care of Lee, we would then have come right in rear of the enemy.
By Mr. Gooch:
Question. Was that your opinion at the time?
Answer. Yes, sir; but I did not express it.[xii]
Question. In what light did you regard the crossing of Lee into Maryland?
Answer. I think the movement of our whole army up the Potomac would have led to the rapid retreat of Lee across the Potomac.
Question. I mean, did you regard Lee s movement as a good or a bad military movement?
Answer. I think it might have been made a very hazardous movement for him.[xiii]
We have to remember that testifying before a Congressional Committee then, like now can be a very dangerous situation for a military man. The radical republicans under Ben Wade control this committee and they are using it as a political hammer to discredit generals who do not display an adequate level of fervor for the cause. Sumner is not particularly identified with any political faction. His credibility comes from a 43-year career in the United States Army holding positions of increasing trust and responsibility.
As an epilogue, Sumner never made it to Missouri. No doubt weakened by a year of active campaigning in the field, Sumner died of pneumonia at his daughter’s home in Syracuse New York only 33 days after testifying.
[i] In testimony before the Congressional committee, Sumner describes Hooker’s Corps as being routed. In his official report dated October 1, 1862, he reports Hooker’s corps, “after a severe contest, had been repulsed.” Note the more negative description in testimony before the committee. By now, Hooker was commander of the Army of the Potomac. Sumner had no love for Hooker.
[ii] The soldiers that Sumner observed laying down on the left were Greene’s division of the Twelfth Corps.
[iii] Sumner takes pains in choosing his words to describe the attack On Sedgwick’s division. He calls it a severe attack and that division faced from it and marched at least a third of a mile before I could stop them. He says that the division did not break but marched in columns to a new defensive position. The connotation is of an orderly, even planned withdrawal.
[iv] It sounds like Sumner wanted to lead all the forces on the right, (his own wing consisting of the Second and Twelfth corps and Hooker’s command in one crushing attack instead as he put it in driblets.
[v] At the battlefield tactical level, Sumner clearly states his intention was to proceed around the enemy left and drive them in front of Franklin, Porter, and Burnside.
[vi] Sumner believed that Hooker faced superior numbers when he went in.
[vii] Sumner believed that there were about an equal number of Federals and Confederate, around 80,000 at the battle.
[viii] Sumner calls the battle a Union victory because the Army of the Potomac held the ground after Lee withdrew.
[ix] Sumner mentions Burnside’s disappointment that Porter did not participate in the attack. Burnside was under the impression that he could call upon Porter for assistance during the battle. When the time came and he requested reinforcements on September 17th, McClellan was only willing to offer him a battery. Sumner mentioning this must imply that Burnside’s disappointment was at least known at the corps commander level if not lower.
[x] The fact that Sumner can’t describe the reason for the delay in pursuing Lee speaks to his diminished role in the Army. Though the senior major general in the Army of the Potomac, McClellan never brought Sumner into his inner circle and explained his reasons for not pursuing Lee immediately. Sumner is left to draw his own conclusions.
[xi] Sumner ascribes the Confederate force that captured Harpers Ferry as having about 30,000 men. Special Order 191 described Longstreet’s force as the “main body” of the Confederate Army. If Sumner was privy to any of McClellan’s thoughts on responding to the discovery of these orders, he may have felt that Longstreet had around 50,000 men under his command.
[xii] At the operational level, Sumner apparently opposed McClellan’s plan to advance in a northwesterly direction across a wide front into western Maryland. He favored advancing along the south bank of the Potomac to Harpers Ferry to cut off the advancing rebels. He never expressed his opinion.
[xiii] Sumner viewed Lee’s audacious advance into Maryland as a “very hazardous movement.”