McClellan at Antietam

ErnieMac

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I recently completed reading The Cornfield: Antietam’s Bloody Turning Point by David A. Welker. In the book he postulates a view of McClellan that I have not read before and think worthy of discussion. The author does not agree with commonly held beliefs that McClellan was overcautious, which resulted in no attacks being made on September 16 as soon as Federal troops arrived on site or on the September 18th as a follow up to the previous day's battle. Welker's opinion is that McClellan was bold enough, but was also a meticulous planner who would not commit himself until he thought all his ducks were in their proper rows (my analogy). Welker also opines that McClellan did not react well to the fluid situation on a battlefield and had difficulty making adjustments on the fly.

As a result McClellan arrived on the field on the 15th and spent most of the following day observing the Confederate lines and making his plan. Satisfied, McClellan attacked the following day. After the battle on the 17th, the Army of the Potomac was in position to attack again. Welker's opinion is that without a developed plan, McClellan sat still on the 18th, preparing for an attack the following day. This, of course, never happened since Lee had retreated the previous night.

Many of you have strong opinions concerning McClellan. I'd be interested in your thoughts.
 

67th Tigers

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Two divisions of McClellan's army arrived near the Portertown (middle) bridge on afternoon of the 15th, and there was an artillery duel.

On the morning of the 16th, he had Hooker's 1st Corps camped north of Keedysville, and 4 divisions of 2nd (-) and 12th Corps were strung out along the road from Keedysville back to South Mountain. The 9th and 6th Corps were in the Pleasant Valley facing towards Harper's Ferry.

It was foggy that morning an hard to see the situation, but by noon McClellan had a plan and was implementing it. He told Burnside to bring the 9th Corps opposite the southern bridge (now the Burnside Bridge) and rode to tell Hooker to push the 1st Corps over the Pry (upper) Bridge and across the Pry Ford and take position astride the Hagerstown Pike. The 12th Corps was also ordered to hurry to the field. Many, including Hooker, considered McClellan to be almost reckless with this movement.

The 12th Corps is approaching Keedysville about 1800, and is ordered to follow Hooker immediately. They don't start moving for about 5 hours. Burnside only got one division into position by nightfall, and the rest of 9th Corps camps well away from the bridge. Franklin is ordered to march to the field with 2 divisions the next morning. Sumner is ordered to be ready to cross the Antietam before dawn the next day, but French's division is a confused mess and not read to move until about 0730.

If anything, McClellan is too aggressive and ambitious in his movements. None of the 2nd, 9th or 12th Corps are where they are supposed to be the next morning. McClellan adapts as best he can in the chaos. He sends Sumner with 2 divisions to reinforce Hooker as soon as they can go. His orders to Sumner were unfortunate in the amount of latitude given, directing Sumner to attack into the West Woods, but if he could spare a division to send it towards the Sunken Road. By 0900 Smith's division has arrived and he sends Richardson and Smith to reinforce Sumner.

He'd ordered Burnside to attack at 0800, but reiterated the order about 0910. However, McClellan then decided to supervise the right on the right in person. The reason the Irish Brigade gave "three cheers for General McClellan" before they charged is he was there, telling Richardson to make the bayonet charge.

When McClellan returns to his CP, or shortly after, Burnside carries the bridge. Sometime after McClellan returned to Sumner on the right as Sumner and Franklin were fighting about whether to attack again (after Slocum's division arrived). McClellan sided with Franklin, and sent for the last reserve to stiffen this attack - two brigades of Morell's division. It seems news of AP Hill hitting Burnside reached him, as he then rode to Burnside's HQ, halting Morell's men at the Pry Bridge as he rode past them (which was about 1600 ISTR). We know he told Burnside to hold the bridge at all costs, and then returned to his CP. He recalled Morell's men to the centre and at 1820 had them in hand and ordered Burnside to counterattack, and he'd advance 5th Corps on his right. Of course it never happened.

I certainly wouldn't say McClellan was being a perfectionist. He was adapting to the changing situation on the fly, and never lost control of it.

The question of the renewal of the offensive on the 18th is another matter. He certainly gave the order to, but then suspended it after it was clear just how badly damaged his own army was.
 

Jamieva

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I recently completed reading The Cornfield: Antietam’s Bloody Turning Point by David A. Welker. In the book he postulates a view of McClellan that I have not read before and think worthy of discussion. The author does not agree with commonly held beliefs that McClellan was overcautious, which resulted in no attacks being made on September 16 as soon as Federal troops arrived on site or on the September 18th as a follow up to the previous day's battle. Welker's opinion is that McClellan was bold enough, but was also a meticulous planner who would not commit himself until he thought all his ducks were in their proper rows (my analogy). Welker also opines that McClellan did not react well to the fluid situation on a battlefield and had difficulty making adjustments on the fly.

As a result McClellan arrived on the field on the 15th and spent most of the following day observing the Confederate lines and making his plan. Satisfied, McClellan attacked the following day. After the battle on the 17th, the Army of the Potomac was in position to attack again. Welker's opinion is that without a developed plan, McClellan sat still on the 18th, preparing for an attack the following day. This, of course, never happened since Lee had retreated the previous night.

Many of you have strong opinions concerning McClellan. I'd be interested in your thoughts.

That would follow his pattern at Yorktown and when he got stalemated in front of Richmond before Johnston attacked at Seven Pines
 

ErnieMac

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I am a little confused by the statement that the 2nd, 9th and 12th Corps were out of position. The 12th Corps had crossed the Antietam the previous evening and was in position on the J. Poffenberger farm about 1 to 1-1/2 miles behind Hooker by 2:00 a.m. Hooker knew they were there and could have repositioned them had he thought that necessary. Mansfield marched to the front at the opening of the battle. Sumner's 2nd Corps was on the east bank of the Antietam waiting for McClellan's orders to advance. McClellan did not give those orders to move Sedgwick's and French's Divisions until 7:20 a.m., nearly two hours after the battle had opened, and Richardson's orders came an hour after that (according to Sumner's report). It is also my understanding that McClellan personally supervised the positioning of Burnside's 9th Corps on September 16.

IMO It seems to me the 2nd, 9th and 12th Corp were not out of position. The 12th Corps was under Hooker's immediate command and was moving forward when the battle opened. The 2nd Corps moved on McClellan's orders. The 9th Corps didn't move on McClellan's orders, but was where he had placed them.
 

Andy Cardinal

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I thought Welker's analysis was interesting. Specifically, he placed a lot of blame on Hooker for McClellan's plan unraveling on September 17.

I think there is a certain amount of truth in Welker's analysis. I believe it might be overstated a bit, but I would have to really study his arguments more than I have to this point. McClellan would be far from the only general who didn't adapt real well when his initial plan unraveled.
 

Scott1967

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He'd ordered Burnside to attack at 0800, but reiterated the order about 0910.

Their is no proof he ordered the attack at 0800 this is what McClellan said in 1863 but Cox disputes this and more than likely the order was indeed at 0910 which would explain why both Burnside and Cox state they received it at around 0945.

And yes im quite aware Cox changed his story but then again so did McClellan.
 

67th Tigers

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Their is no proof he ordered the attack at 0800 this is what McClellan said in 1863 but Cox disputes this and more than likely the order was indeed at 0910 which would explain why both Burnside and Cox state they received it at around 0945.

And yes im quite aware Cox changed his story but then again so did McClellan.
Yeah, then explain why Kingsbury attacked at 0900. Explain why everyone who recorded Burnsides order for them to attack the bridge gave it as 0900, including Cox whosaid he received the order at 0900 in his AAR. He redacted this postwar to fit Burnside.

The regimental commanders, brigadiers, division commanders etc. had mostly done their reports by 22nd September. Cox gives his report on the 23rd September. Everyone who comments says 0900.

On 29th September (the day before Burnside submits his report) McClellan writes his wife:

"I have been hard at work all day upon a preliminary report of the recent battles, and find that, in order to arrive at anything like the truth, I must tomorrow take all my aides to the ground and talk with them there. I would really prefer fighting three battles to writing the report of one. You can hardly imagine the difficulties of such a task. You are necessarily combating the amour propre, the vanity of every officer concerned when you say one word in commendation of anybody else. Each one is firmly convinced of the fact that no one but he had anything to do with the result, every commander of a brigade becomes firmly convinced that he fought the whole battle & that he arranged the general plan, of which he knew simply nothing."

"I ought to rap Burnside very severely, and probably will; yet I hate to do it. He is very slow; is not fit to command more than a regiment. If I rap him as he deserves he will be my mortal enemy hereafter. If I do not praise him as he thinks he deserves, and as I know he does not, he will be at least a very lukewarm friend. I mention this merely as an instance that you will comprehend..."

This is incredibly revealing. McClellan knows how badly Burnside has performed, but can't afford to make an enemy of him. Burnside put in his report the next day. It has different timings to everyone else:

1. It places the order which Cox says was handed to him by Burnside before 0700 at around 0800-0900, after the artillery duel which was started by 9th Corps advancing on the bridge at 0800 and ended at 0900 when Eubank's battery was silenced. Hence Burnside is adding two hours or more here to an order those pre-0700 status is undisputed.

2. Burnside says he received the attack order at 1000, and says he directed the 11th Connecticut to advance as skirmishers (this is known to have happened ca. 0800, the rebels report being driven in by them at that hour), and for Crook's brigade to make an assault.

George Crook's brigade of course got lost en route. Capt Christ carried the order to Crook, and Crook replied "What bridge?", but the staff didn't know. They didn't even know what direction the creek was. Crook sent the 28th Ohio to find the bridge, and half the regiment came out 350 yds N of the bridge, and then didn't manage to guide the brigade in, getting lost again.

Simply, Burnside added two hours by the look of things to both timings.

Now, in his 15th October report, McClellan accepted Burnside's timings and in fact gave Burnside effusive praise, excusing Burnside's delays by claiming his task was difficult. This is McClellan giving Burnside "the praise he [Burnside] thinks he deserves, and as I [McClellan] knows he does not". It is purely political.

Did McClellan bend the truth? Yes. However, he bent it in his 15th October report to cover up for Burnside. By August 1863 he saw no further reason to protect Burnside, and told the truth.

It amazes me how some are willing to ignore the overwhelming preponderance of evidence on this matter in an attempt to defend Burnside.
 

Scott1967

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This is incredibly revealing. McClellan knows how badly Burnside has performed, but can't afford to make an enemy of him. Burnside put in his report the next day. It has different timings to everyone else:

Burnside did not perform badly at all in fact he performed well at both South Mountain and Antietam , After all he was the Only Union Corps commander to achieve his objectives.

Just who is McClellan going to blame? Hooker i doubt it his troops had the hardest fighting , Mansfield is dead and Sumner was left out in the cold by McClellan when he made his master plan , Nope the person to blame would be Burnside and what better time to do it when you know your going on a political campaign.

Every Union Commander praised Burnside for his honesty and the fact that he was willing to accept full responsibility for his actions he was nether political or ambitious which sort of made him an easy target when it came to blame game and i would just like to add he showed he was a competent commander but not a consistent one his out manoeuvring of Longstreet and his clever plan at the battle of the Crater which of course again he took the blame even though Grant and Meade were the real culprits.

Burnside might well have carried the day at Antietam if it wasn't for McClellans bungling or in activity of not screening Burnsides flank and thus allowing AP Hill to sneak up and initiate his attack , His refusal to commit his cavalry and hold them back made the difference and nobody is to blame for that except George McClellan in my view.

As for the Order why would Burnside lie? And even if he did lie that was also down to McClellan for dressing down Burnside the night before the attack not a wise thing to do when your trying to motivate your commanders to perform well in the coming battle.

To be fair im going to take Burnside at his word here it would be out of character for him to lie given what I've read on the man it would also be reasonable to presume that an order given at 0700-0800 would be too soon for Lee to withdrew forces to help support his left and centre which was the whole purpose of Burnsides attack.

I think the order was given as stated at 0910 it took 25-30 mins to reach IX Corp and then Burnside more than likely rounded up the number to 1000 am but he probably received it before that 0945-0950 , Cox may have been confused as the fight had started way before the order was received maybe recalling when the fight actually started instead of when the order was received.

Of course this is my personal view on the matter.
 

67th Tigers

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I think the order was given as stated at 0910 it took 25-30 mins to reach IX Corp and then Burnside more than likely rounded up the number to 1000 am but he probably received it before that 0945-0950 , Cox may have been confused as the fight had started way before the order was received maybe recalling when the fight actually started instead of when the order was received.

Of course this is my personal view on the matter.
Seriously, you really are defending Burnside?

Burnside did nothing at South Mountain. Cox commanded 9th Corps. McClellan personally directed the battle, and Burnside was essentially acting as one of McClellan's staff. The next day when the pursuit began, McClellan told Burnside to push the 9th Corps forward, and after sorting out the admin rode forward with Hooker's Corps. Burnside of course took 7 hours to start 9th Corps moving.

How did Burnside achieve is objectives? He was slow, disorganised, and got rolled up like a wet towel, despite having about 90 minutes warning of the approach of AP Hill. No amount of prompting from McClellan could get Burnside to attack, either against the bridge, or when McClellan arranged to counterattack at 1820. In fact, Burnside's complaints of weakness went further, sabotaging any prospect of an offensive on the 18th. On a field where no corps commander truly covered themselves in glory, Burnside was certainly the worst.

It is quite probable than an order was sent at 0910, and from the contents it was almost certainly a repeat of an earlier order (being issued before 0830, when it was written before it was known that Hooker and Mansfield were down). We know that Burnside received many orders from McClellan to attack, and since McClellan departed to supervise the fighting on the right well before 1000, this is likely a later one. This is the third order, the one Sackett carried. There will be no 4th order until close to noon, when McClellan has returned from the right to find Burnside has made no progress and sends Colonel Key with another order to attack "if it cost 10,000 men", and apparently carried a sealed order placing Burnside under arrest for disobeying orders, and placing Morell in command of 9th Corps. It worked, as Sturgis reported receiving the order to take the bridge "at all hazards".

The four orders were:
1st (before 0700) contents as reported by Burnside were to move his force to the bridge
2nd (0800), carried by Lt James Wilson, were to attack immediately
3rd (0910), carried by Col Sackett, were a repeat of the 0800 orders
4th (ca. 1200), carried by Col Key, were peremptory to attack immediately (or be arrested)

There are a lot of circumlocutions made trying to justify it taking 50 minutes for the order to make the 5 minute journey and fit Burnside's account.

Bear in mind, the rebels place the time their piquets on the eastern bank were driven in by Kingsbury as around 0800, and Kingsbury's charge was at ca. 0900.
 

Saphroneth

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It's worth thinking about McClellan's concept of operations, as well - what he's doing is one of the classical ways to attack an enemy position, which is to first draw out enemy reserves in one place by pressuring one flank and then launch an attack in another place (in this case the other flank). The concept relies on the attacks being spaced in time, closely enough that the second one can take advantage of the distraction effect (i.e. the enemy hasn't finished dealing with the first attack and can't turn around to deal with the second one) but distant enough that the enemy has begun reacting to the first attack.

This would imply that the attack on the Union left would come after the attack on the Union right, but there's a lot of prep work that Burnside can do before getting the formal "go" order - he knew what McClellan had planned, and getting supporting artillery into position plus troops in place to attack if need be would be the doctrinally correct thing to do. Even if for some reason Burnside assumed McClellan didn't want him ready to attack, Burnside could still have assumed he'd be wanted ready to defend the bridge (which means troops close by enough to be able to quickly oppose a crossing) and this wasn't done either.

If Burnside had correctly operated his corps, then he would have had:
- At least a division ready to attack the bridge promptly when given the order, probably back half a mile from the bridge itself to avoid taking casualties from artillery fire. This doesn't mean the whole lot go in at once, but that there's regiments ready to supply additional regimental charges promptly if the first one slows and fails rather than long delays between each one.
- Artillery on the heights over the bridge, either in view and conducting an artillery duel (to clear away enemy batteries) or just masked by terrain (to come into view promptly when called for)
- A brigade in position to mount a flanking attack on a known ford which had been examined and considered practical that day.
- The rest of the corps formed up, probably in column, to quickly pass over the bridge once it was gained - or march to join the troops attempting to force a crossing, if the crossing was opposed heavily enough that a division couldn't force it by themselves.

This is operating the corps as a corps. It means that you're using the constituent parts to achieve your goal, and you're doing so cognizant of what the goal is and what the enemy could do to oppose you - if they have artillery defending the bridge you can win the artillery duel, if they have a small force of infantry your attacking division is available to push them away, if they have a large force of infantry you have a flank attack developing, and if the enemy has enough strength opposing you to successfully hold off both the divisional frontal attack and the brigade-strength side attack along the line of the creek then they are at least committing enough strength that you're materially affecting the fighting to the north.


The Battle of Antietam took place almost exactly at the equinox, and what this means is that we know sunrise (dawn) was just before 6AM. While it would be expecting too much for the corps to be all awake, breakfasted and in position by dawn, it should certainly have been possible for them all to be in position by 8AM.


This might be argued to have ruined the surprise value of the assault on the bridge, but
(1) if seeing the pending assault leads Lee to keep back extra troops in case of a crossing then that's pulled reserves away from the fight in the north anyway and
(2) what actually happened didn't exactly exploit surprise value, which sort of invalidates the point.



Now, it's possible to argue that perhaps McClellan somehow got over-focused on the Union right wing and forgot to send the signal to commence, but the evidence is quite strong that he did order the attack earlier. We have large amounts of corroborating evidence for the 0910 order not being the first order:

- Burnside said that Sackett (who carried the 0910 order) was the "third or fourth" man to give him the same order
- The 0910 order's description of the northern flank has units in their positions from well before 0910, which makes it probable that the 0910 order is simply a "repeat" and exact copy of an earlier order
- All lower-level sources (regimental and brigade) on both sides who mention the start of the fighting mention it as being before 0910
- Cox mentions an order "before 0700" in one report; he has no motive to make this up
- Wilson's account mentions that he carried an order issued at 0800.

Effectively, for the 0910 order to be the first order (and to arrive late enough that Burnside's claim of ordering the attack at 1000 wouldn't be overly late), it would have to be an order written with a description of the positions of units from an hour before without any reason to do this; the man who carried it (Sackett) would have to be lying about Burnside saying it was the "third or fourth" order; Cox would have to invent the order before 0700 to damage Burnside, without any motive; the lower-level (regiment/brigade) officers who gave the start of the fighting at around 0900 would have to be lying; the order would have to take fifty minutes to get to Burnside and be actioned; Wilson would have to be lying about there being an order he carried.

And even if all that were true and the order only arrived between 9 and 10, and Burnside attacked at 1000, Burnside would still have screwed up! With four hours since dawn to get his division in place it should have been ready to go on a moments' notice, indeed he should have been champing at the bit to get involved given the intense fighting taking place elsewhere on the field, and it shouldn't then have taken until the afternoon to actually get troops over the bridge.


The more parlous explanation is that:

- Burnside screwed up.
-- Burnside lied in his report to cover his screwups, rejecting the timings given by all his subordinates.
-- McClellan accepted the timings rather than provoke further discord with a commander who he'd have to deal with regardless, but knew the report contained false timings.
-- Cox later adopted the "anti-McClellan" line of argument even when it conflicted with his own personal recollections (as we know from other cases).

This minimizes the number of people making things up, and gives explanations for why they did.
 

ErnieMac

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IMO @Saphroneth has hit on a major reason the Army of the Potomac did not achieve a more successful outcome at Antietam when he discusses "operating the corps as a corps". It seems McClellan's strategic plan called for corps attacks first by the 1st and 12th Corps (Hooker) on the right, second by Burnside on the right and finally, as McClellan state in his Official Report, in the center with "any reserve I might then have on hand". It is my personal opinion that would have been Sumner's 2nd Corps had events played out as hoped, but Sumner was directed to the right when Hooker bogged down.

The corps commander level is where corps operations seem to have broken down. Hooker piecemealed his attack, sending in division after division instead of a coordinated corps attack. Burnside did the same. Sumner led with his first (Sedgwick) division and lost control of the other two. Had any all of these three efforts, or maybe even just one, been well coordinated the results of the battle could have been substantially different.
 

Saphroneth

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Management of corps as corps is kind of tricky, but it's worth realizing that you wouldn't necessarily want a corps attack to hit all at once (on the tactical scale) as a single overwhelming sledgehammer. It's quite reasonable to have a corps attack be 2-up 1-back (in divisional terms) or 1-up 2-back, or similar - you have some brigades or divisions making the initial attack and others available to follow up success or mitigate failure, while if they all go in as a single line then the attack is fragile (as a repulse anywhere can cause panic to spread, and a counterattack can break the whole corps at once, without a reserve to commit).

Given how attacks sometimes went elsewhere in the war I'd call an attack where a whole corps is moving in the same direction at the same time (and it's the right direction) to be at least "as good as average" if not somewhat better; there's plenty of room for improvement in the north, but what it actually did still compels Lee to commit his entire reserve.

Burnside's articulation is a complete mess though.
 
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There are some interesting and tenable pro-McClellan arguments here. However, you can't make McClellan a highly aggressive general, because he wasn't. I'm not a McClellan hater, mind you. In pondering the orders for the morning attack south of the bridge for 9th Corps research I'm doing, I'm not that supportive of McClellan, although command failures on the army's southern flank were far from his alone. Just remember the one sentence that sums up McClellan more than any other. He wrote this to defend not attacking on the 18th: "success of an attack on the 18th was not certain." Success in the attack of the day before was far from certain either. Success in war is never certain. Regardless of any failure of Hooker, Cox, or Burnside, the commanding general is the ultimate in responsible for the conduct of his army on the field. Perhaps if McClellan held a council of war on the night of the 15th or 16th, issued clear orders, and placed at least two corps across the Antietam north of town by noon on the 16th, we wouldn't be having this conversation.:smile coffee:


 

Saphroneth

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There are some interesting and tenable pro-McClellan arguments here. However, you can't make McClellan a highly aggressive general, because he wasn't. I'm not a McClellan hater, mind you. In pondering the orders for the morning attack south of the bridge for 9th Corps research I'm doing, I'm not that supportive of McClellan, although command failures on the army's southern flank were far from his alone. Just remember the one sentence that sums up McClellan more than any other. He wrote this to defend not attacking on the 18th: "success of an attack on the 18th was not certain." Success in the attack of the day before was far from certain either. Success in war is never certain. Regardless of any failure of Hooker, Cox, or Burnside, the commanding general is the ultimate in responsible for the conduct of his army on the field. Perhaps if McClellan held a council of war on the night of the 15th or 16th, issued clear orders, and placed at least two corps across the Antietam north of town by noon on the 16th, we wouldn't be having this conversation.:smile coffee:


I think there are a couple of responses to make here.

Firstly, the bit about what McClellan wrote to defend not attacking on the 18th - what McClellan is doing here is not simply saying "success isn't certain, therefore I didn't attack", because that wasn't his reasoning. That wasn't his reasoning on the 17th (when success still wasn't certain, as you correctly identify, and he did attack). What McClellan is doing is saying that success was unlikely and not worth the risk.
The question about whether it was worth the risk is a fair question, but it's one you have to consider properly.

As for the second point about placing at least two corps across the Antietam by noon on the 16th, this would be a hell of a trick because as of noon on the 16th there weren't really two corps to do that with. 1st Corps was in hand to begin crossing, but 2nd Corps was still only just arriving (two divisoins strung out from Keedysville back towards South Mountain, with 12th Corps behind them in the column; the third division was McClellan's central reserve), and to feed them over the Upper Bridge would take many hours (which is how long it took historically).


Out of curiosity, what's the cause for the belief that McClellan didn't issue clear orders? I want to make sure it's based on positive evidence (i.e. "we know what the orders were and they were not clear") rather than negative evidence (i.e. "if McClellan had issued clear orders they would have been successful, therefore he didn't")


My understanding of Antietam is basically that McClellan launches attacks which amount to four distinct corps-level attacks, despite the breakdown of coordination (as he'd originally been going for one "wing level" attack in the north). These attacks inflict heavy casualties on the Confederate army, but ultimately run out of steam, and McClellan stops attacking pretty much once he no longer has spare troops beyond those he needs to maintain his line.

In the process McClellan sends in a total of about 75% of his army in attacks in a single day. It's just that that's not enough to hammer Lee under (Lee has a smaller army but not much smaller) and so it's merely a battle in which McClellan inflicts heavy casualties and also forces Lee to withdraw from the North.
 
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I think there are a couple of responses to make here.

Firstly, the bit about what McClellan wrote to defend not attacking on the 18th - what McClellan is doing here is not simply saying "success isn't certain, therefore I didn't attack", because that wasn't his reasoning. That wasn't his reasoning on the 17th (when success still wasn't certain, as you correctly identify, and he did attack). What McClellan is doing is saying that success was unlikely and not worth the risk.
The question about whether it was worth the risk is a fair question, but it's one you have to consider properly.

As for the second point about placing at least two corps across the Antietam by noon on the 16th, this would be a hell of a trick because as of noon on the 16th there weren't really two corps to do that with. 1st Corps was in hand to begin crossing, but 2nd Corps was still only just arriving (two divisoins strung out from Keedysville back towards South Mountain, with 12th Corps behind them in the column; the third division was McClellan's central reserve), and to feed them over the Upper Bridge would take many hours (which is how long it took historically).


Out of curiosity, what's the cause for the belief that McClellan didn't issue clear orders? I want to make sure it's based on positive evidence (i.e. "we know what the orders were and they were not clear") rather than negative evidence (i.e. "if McClellan had issued clear orders they would have been successful, therefore he didn't")


My understanding of Antietam is basically that McClellan launches attacks which amount to four distinct corps-level attacks, despite the breakdown of coordination (as he'd originally been going for one "wing level" attack in the north). These attacks inflict heavy casualties on the Confederate army, but ultimately run out of steam, and McClellan stops attacking pretty much once he no longer has spare troops beyond those he needs to maintain his line.

In the process McClellan sends in a total of about 75% of his army in attacks in a single day. It's just that that's not enough to hammer Lee under (Lee has a smaller army but not much smaller) and so it's merely a battle in which McClellan inflicts heavy casualties and also forces Lee to withdraw from the North.

Thanks much for your thoughts here. I think the period between South Mountain and the attacks of the 17th is the most fascinating tactical situation of the war. You make commendable points. I don't think we're far apart on the general idea. Perhaps two corps couldn't be over the creek by noon. I bet bolder generals might have found a way, especially since we are talking 36 full hours since South Mountain on the morning of the 16th (even after the fog). I don't think McC was looking for a major battle after South Mountain. Carman has good points on that subject.

I'm not in total agreement on your analysis of McC's defense of his decision on the 18th. He felt without absolute certainty, he would not attack due to the circumstances. He certainly mentioned the risk involved, but he also wrote of his "narrow view of the condition of the country" and another battle needed "absolute assurance" of the best outcome. Again, he wished for something no army commander could ask in war at a time when Lee's own battered troops had a river with one ford at their back. Any "narrow view of the condition of the country" from the other general's perspective makes McC look a bit over cautious. If Lee had 120K men along the Antietam, as McC suggested he did, why attack at all? One corps across the creek against 120K Confederates?

You are right that clear orders would not have guaranteed a better outcome. Yet, I have seen no pre-battle written attack plan regarding McC's goal for the 17th. I've never seen a source showing there was a council of war before the battle. McC changed his story after the war. I have no problem with those critical of Hooker on the 16th or 17th, but McC does not deserve a pass (and I'm not saying you are giving him one).

I don't think an attack by a wing was McC's original plan. It appears his biggest concern was making sure Sumner did not command it. Thus, the late arrival of the 2nd Corps west of the Antietam. McC wrote of a plan where four corps would attack from the north, but that was after so much heat went his way for lack of a better outcome at Sharpsburg. The 12th Corps was added to the northern attack after Hooker requested it on the 16th (unless every source I've ever seen but McC's postbattle comments are wrong). If you have a cite for McC's original desire to for the 12th Corps to join Hooker for a dawn attack, I'm all ears. Perhaps Hooker should've had Mansfield by him at dawn. I'm not certain McC ordered it or visualized it. Hooker should have, fine. I'm not even convinced Hooker knew where Mansfield was in the overnight period. Do you know of any written communication between the two generals that night?
 

Saphroneth

Major
Joined
Feb 18, 2017
Thanks much for your thoughts here. I think the period between South Mountain and the attacks of the 17th is the most fascinating tactical situation of the war. You make commendable points. I don't think we're far apart on the general idea. Perhaps two corps couldn't be over the creek by noon. I bet bolder generals might have found a way, especially since we are talking 36 full hours since South Mountain on the morning of the 16th (even after the fog). I don't think McC was looking for a major battle after South Mountain. Carman has good points on that subject.
In the first place, it's pretty much a rule of thumb that only 30,000 men can fit down a road in a day. So one full day's worth of that time would be consumed in just getting the troops over South Mountain under normal operations - there was a truly massive traffic jam - then it's about 5-6 miles, or the majority of a day's march, from the South Mountain gaps to Keedysville.

I can certainly buy the idea that a well coordinated army would have done better, but McClellan wasn't using a well coordinated army. He'd had only about a week to organize it before leaving Washington and some of the details were still being thrown together on the march.
As for the idea McClellan wasn't looking for a major battle after South Mountain, if that were true he could have just thrown 1st and 12th Corps across the creek and held them in position around Smoketown and Mercersville. Instead, he attacked; he was willing to take the battle on the 17th, and indeed make an attempt at a battle of annihalation (and ended up producing a battle of attrition in his favour).


I'm not in total agreement on your analysis of McC's defense of his decision on the 18th. He felt without absolute certainty, he would not attack due to the circumstances. He certainly mentioned the risk involved, but he also wrote of his "narrow view of the condition of the country" and another battle needed "absolute assurance" of the best outcome. Again, he wished for something no army commander could ask in war at a time when Lee's own battered troops had a river with one ford at their back. Any "narrow view of the condition of the country" from the other general's perspective makes McC look a bit over cautious. If Lee had 120K men along the Antietam, as McC suggested he did, why attack at all? One corps across the creek against 120K Confederates?
This simply doesn't hold. McClellan's in a situation where he has basically no spare troops to attack with on the 18th, and what that means is that if he attacks anyway and is defeated then Lee can counterattack and wreck his army; the Union has suffered several defeats in a row which have caused panic, and can't endure another.
(That's what the "condition of the country" means.)
McClellan's attacks on the 17th don't risk his army, because he always has enough troops in hand to recover the situation if the attack fails. An attack on the 18th would risk his army, because it'd be using his last reserves, or if he didn't overcommit it would be too small an attack to have any effect (a couple of brigades).

As for the size of Lee's army, I suspect that McClellan thought Lee might have had 120,000 Aggregate Present at the most (which is an army about the same size as McClellan's own on the field). This is an estimate which has at least some reasoning behind it, and is basically flawed because the Union reconstruction of the Confederate ORBAT is flawed (they missed the brigades left behind to defend Richmond).
McClellan's actions make sense if he thought that Lee's army was close in size to his own.


You are right that clear orders would not have guaranteed a better outcome. Yet, I have seen no pre-battle written attack plan regarding McC's goal for the 17th. I've never seen a source showing there was a council of war before the battle. McC changed his story after the war. I have no problem with those critical of Hooker on the 16th or 17th, but McC does not deserve a pass (and I'm not saying you are giving him one).
My understanding is that 12th Corps were ordered over the creek on the 16th, and basically that they began crossing as soon as 1st Corps finished crossing the bridge; this may be wrong, of course. 2nd Corps pulls in to support the possibility of an attack over the middle bridge, so as the corps arrive it's:
1st Corps (arrives first) - goes to upper bridge (as that's where McClellan needs troops then)
2nd Corps (arrives second) - goes to middle bridge (so there's troops to support an attack there if needed)
12th Corps (arrives third) - goes to upper bridge (to bulk out the flank attack)
Then 2nd Corps is diverted to the upper bridge later on. Richardson's Division isn't sent until McClellan has another division to make up his central reserve in their place (Morell).

The coordination is messed up because it's an army with officers that haven't worked together and some that have never held high command before. The exegiencies of how Burnside's wing got split up after South Mountain and the way that corps are being moved around according to which is in the best physical location to do what's needed mean the command structure gets scrambled.

i.e. Hooker (who is the first officer over the creek) is new to corps command, and is doing okay considering but hasn't yet got into the habit of coordinating someone else's corps as well as his own.
Mansfield (commanding 12th Corps) is new to corps command also, and stuffs it up acting like a junior officer.
Sumner (commanding 2nd Corps) is not new to corps command, but goes to the wrong place and doesn't find McClellan for a discussion overnight; he's also been working hard keeping his wing going in the right direction, because at one point 12th Corps turned north at Boonsboro and had to be redirected.

Under the circumstances, it's if anything surprising the attack in the north did so well; certainly getting 45,000 men PFD attacking on the same axis in a single day is one of the largest attacks of its type in the war.
 
Joined
Dec 22, 2016
Location
NH
The 12th Corps wasn't crossing for hours after the 1st Corps. The 12th only had to go a couple of miles, and several units weren't in camp at the Line Farm until midnight or later. You are right to say a lack of coordination prevailed among generals not that familiar with each other. Hooker was in charge on the west side of the creek, and he didn't do enough. But the overall lack of communication has to go at the feet of the general commanding the whole army. The 1st Corps was crossing way later in the day then necessary, if the plan was for only one corps to lead, with a second following later in the day.
 

Saphroneth

Major
Joined
Feb 18, 2017
The 12th Corps wasn't crossing for hours after the 1st Corps. The 12th only had to go a couple of miles, and several units weren't in camp at the Line Farm until midnight or later. You are right to say a lack of coordination prevailed among generals not that familiar with each other. Hooker was in charge on the west side of the creek, and he didn't do enough. But the overall lack of communication has to go at the feet of the general commanding the whole army. The 1st Corps was crossing way later in the day then necessary, if the plan was for only one corps to lead, with a second following later in the day.
So that I'm clear, what's your proposal for when troops do what?

12th Corps started the day strung out behind 2nd Corps, and with 1st, 2nd, 9th, 12th Corps and Sykes' division all trying to get down the National Road I wouldn't want to assume that by the morning of the 16th the whole of the forces were west of South Mountain. 12th Corps arrived in the mid-late afternoon (the time I have is around 6pm at Keedysville) and were sent over the bridge then; they took ages to get over, but that's what happens when you try to fit over 10,000 men PFD, many of them inexperienced, over a narrow bridge during the evening and after dark.
They get diverted as soon as they arrive.

In addition to how long it took 12th Corps to turn up (which is partly the result of the screwed-up state of what used to be Banks' corps - it's not like McClellan can go and spend hours personally directing traffic to get it all thrashed out, Sumner was already trying to get his two corps organized - and partly simply that they were last in the march column, with the rear possibly still departing Frederick on the morning of the 15th) there's also one of the other reasons why a defile results in a delay - you need enough force on the far side of the bridge that you can advance to contact, rather than simply route-marching through. (This would act to delay 1st Corps a bit.)


Basically what happens at Antietam is not that far off the kind of friction that happens in any major troop movement. There's enough of this sort of thing in the Waterloo campaign, and that was between professional armies with staffs that had been serving for years - consider the way that one corps in the Prussian movement interrupts another, and how a fire in a village delays that corps for hours - but Antietam has this perception of "a great missed opportunity because McClellan was a screwup" but the reason McClellan is considered a screwup is "because he missed a great opportunity at Antietam". It gets kind of circular.

What actually happens at Antietam is that McClellan (with a total of about 190 regiments on the field at some time during the 17th) goes for several large attacks against Lee (with a total of about 180 regiments on the field at some time during the 17th). McClellan's attack suffers from the usual friction plus some issues with the cobbled-together state of the army, but inflicts heavy casualties without overcommitting.
 

67th Tigers

1st Lieutenant
Joined
Nov 10, 2006
The real question is whether McClellan should have waited a day?

McClellan literally attacks ASAP, pushing his forces in aggressively before they're all up, and hence there is some lack of co-ordination. If what you want is a neat, well ordered set-piece battle, then you'd have to wait until the 18th and maybe even the 19th.

There is, of course, no possibility of McClellan attacking on the 15th. Only two divisions of infantry made it to the field by dusk that day. Around dusk the 1st Corps is nearing the field, and McClellan directs them north of Keedysville to cover the bridge there.

On the morning of the 16th the situation is that two divisions are at the Middle Bridge, and the 1st Corps are encamped north of Keedysville. There are 5 divisions and a brigade along the road back to Frederick (the other two divisions of 2nd corps, then 12th Corps who are astride South Mountain, with Morell and a brigade that will be assigned to 2nd Corps back at Frederick). The 6th and 9th Corps had been turned south towards Harper's Ferry, and the 9th Corps has orders to march to the Antietam.

At 1100 on the 16th, McClellan rides with Burnside down to the area of the lower bridge and gives Burnside orders to bring his corps there ready to attack at dawn the next day. McClellan goes so far forward that he comes under sniper fire. When he returns to his HQ at Portertown at noon, Sumners 5 bdes are up and sorted out. McClellan rides to Hooker and orders the 1st Corps over the bridge. He gets on with various tasks and then joins Hooker over the bridge. In the late afternoon rides back across the creek to Hooker's HQ at the Pry House, orders 12th Corps to follow Hooker when they arrive, and Sumner to be ready to move at dawn the same way. He tells Sumner that for the moment he is at Hooker's Pry House HQ.

In the late afternoon the 12th Corps arrive at Keedysville, followed by Weber's brigade (passed Keedysville about 1600) and then Morell's division (the lead of which reached Keedysville around 1700). There is a major question about 12th Corps - although the 2nd Corps cleared the road with the night-march McClellan ordered, they didn't start marching until about noon, i.e. as per the schedule. Hence they didn't reach Keedysville until the late afternoon.

Burnside's deployment was a confused mess. Only Rodman with 2 brigades reached the bridge on the 16th. The rest of the corps weren't even ordered forward to the bridge by Burnside until ca. 0900 on the 17th (responding to McClellan's 0800 order to attack one assumes).

So, when discussing the possibility of a 16th September attack, it must be remembered that McClellan lived in the real world and that his subordinates didn't have nearly the sense of urgency he did. Sumner, once given the order to make a night march and get to Antietam unquestioningly executes it. However, he apparently makes no provision to push Mansfield on. Mansfield just obeys the march schedule set out the day before by Sumner. McClellan ordered 12th Corps to support Hooker well before they arrived, and had they marched at daybreak instead of noon, the 12th Corps would have linked up with Hooker late afternoon of the 16th.

To mount an attack on the 16th means doing it with the 1st and 2nd Corps, and Sykes' divisions. No-one else arrives in time. By noon of the 16th, Jackson's, Ewell's and Walker's divisions had arrived, and Lee probably had the stronger army on the field.

If Hooker had moved in the morning, it would be completely unsupported. He complained that he'd be "eaten up", even with 12th Corps moving to support him and 2nd Corps ready to follow. How much worst if he was sent completely isolated to fight Jackson, Hood and DH Hill on his own. As we can see from the fighting of the 17th, 1st Corps would have been overwhelmed and destroyed..

We know that on the 17th, many of the corps commanders were pretty tardy. If you want a concerted attack then you have to wait until the 18th.
 

Saphroneth

Major
Joined
Feb 18, 2017
It seems as though one of the basic problems at Antietam (including the movement from South Mountain, and indeed the fighting at South Mountain) was that McClellan could only be in one place at a time. And we notice the places where we might be able to point and say "McClellan could have helped here", but McClellan was also doing things in the places where he actually was so you end up with one of these things needed:

1) More than one McClellan.
2) Instant communications and good information on what one's own army is doing.
3) McClellan's battle sense being so heightened and his horsemanship (and horses) so good that he can ride around like a lunatic going to all the trouble points as they emerge, in the manner of Wellington but with an operational space larger than many Wellington commanded.
4) Subordinates who are more capable, on average, and who follow the existing orders promptly.

(1) is of course impossible.

(2) is the sort of thing normal for the 1940s, or for when someone is playing a computer game, but not really feasible in the 1860s over a large battlespace. Even with radio it might not work.

(3) might work, but it doesn't merely require McClellan to be basically competent - it requires McClellan to be on par with one of the greatest commanders of history.

So (4) is the most plausible, and in many cases the shortcomings are with the commanders - the orders are there but the execution isn't.


Hooker and Mansfield are the two officers who were recent McClellan picks to lead their corps, so it's plausible that there's some McClellan choice going on there which conceivably could have gone a different way. I'm not sure however who the alternatives would have been, as Mansfield was quite senior so the choice might well be him or leaving AS Williams in charge; Hooker was assigned in from 3rd Corps, and in fact was the only division commander of 3rd Corps who'd survived to that point, so again he's quite senior.
 
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