The Tale Untwisted

[Saphroneth]

How indeed, perhaps little Mac as Commanding General, should have made it his business to know. What, for instance, was Union Cavalry doing all this time and was he reading intel. reports from Washington?

The original of this was:

P.S. It always intrigued me that the confederate force from Harpers Ferry, was able to force march to Antietam, without McClellan anticipating and being prepared for just such an event?

And the answer is simple - there is absolutely no reasonable way for McClellan to block them. They are marching along the southern side of the Potomac, and so the Potomac is in the way. The only preparation he can really make is:


1) Setting it up so that the arrival of any significant enemy on the 17th itself will be communicated to his flank commander, Burnside, in so far as that's his responsibility.
2) Acting so as to maximize the chances that he will be able to focus on Lee before Lee gets reinforcements, while still allowing time for his own attack to be made with the greatest strength.
3) Attempting to cut Lee's forces at Sharpsburg itself off from the Potomac.


He did all these things. (The arrival of AP Hill was communicated to 9th Corps well in advance fron a signals station, in fact.)

The simple geography of the situation means that even if McClellan does know about the enemy force-marching from Harpers Ferry to Antietam there's not a lot that it does to influence his dispositions, except that he can't attack in full force on the 16th with whatever would overwhelm DH Hill and Longstreet if they hadn't been reinforced - because they had been, by Jackson's forces arriving early on the 16th.

If it had been possible to block the arrival of reinforcements then that's a whole different question, but there's no way to actually do so. The Antietam is a wide and deep river and there's no crossing between Harpers Ferry and Shepherdstown.

 

[OpnCoronet]

The original of this was:


And the answer is simple - there is absolutely no reasonable way for McClellan to block them. They are marching along the southern side of the Potomac, and so the Potomac is in the way. The only preparation he can really make is:


1) Setting it up so that the arrival of any significant enemy on the 17th itself will be communicated to his flank commander, Burnside, in so far as that's his responsibility.
2) Acting so as to maximize the chances that he will be able to focus on Lee before Lee gets reinforcements, while still allowing time for his own attack to be made with the greatest strength.
3) Attempting to cut Lee's forces at Sharpsburg itself off from the Potomac.


He did all these things. (The arrival of AP Hill was communicated to 9th Corps well in advance fron a signals station, in fact.)

The simple geography of the situation means that even if McClellan does know about the enemy force-marching from Harpers Ferry to Antietam there's not a lot that it does to influence his dispositions, except that he can't attack in full force on the 16th with whatever would overwhelm DH Hill and Longstreet if they hadn't been reinforced - because they had been, by Jackson's forces arriving early on the 16th.

If it had been possible to block the arrival of reinforcements then that's a whole different question, but there's no way to actually do so. The Antietam is a wide and deep river and there's no crossing between Harpers Ferry and Shepherdstown.

So once again, McClellan had nothing to do with the surprise flank attack by Hill, it was Burnside's fault, or was it the Geography? It really is hard to keep track of all the excuses.

P.S. Are you sure of the line of march of the confederate reinforcements from
Harper's Ferry ?

 

[67th Tigers]

So once again, McClellan had nothing to do with the surprise flank attack by Hill, it was Burnside's fault, or was it the Geography? It really is hard to keep track of all the excuses.

P.S. Are you sure of the line of march of the confederate reinforcements from
Harper's Ferry ?

It wasn't a surprise. Burnside got 90 minutes warning to the effect the AP Hill was crossing the river. The problem was, Burnside didn't do anything with that 90 minutes.

The troops from HF crossed in the rebel rear, at Boteler's Ford. They could not be interdicted.

 

[OpnCoronet]

While I agree there are times McClellan could have been more aggressively, it is not correct to say that McClellan wasted 24 hours before attacking on September 14. The infantry fight at Fox's Gap opened less than 24 hours after McClellan first saw the orders. Cavalry and artillery opened sooner. In fact U. S. Cavalry pushed the Confederates back to South Mountain all day in September 13 (beginning before the orders were found).

I don't know where McClellan could have started the battle a few hours earlier. The fighting at South Mountain started around 7 am with infantry engaging at little before 9. The fighting at Antietam began on September 16 and resumed before dawn on September 17.

I still contend that Franklin could have attacked at Crampton's Gap earlier than he did one September 14.

I believe McClellan made mistakes but he was not incompetent as many would make him out to be.

While I agree there are times McClellan could have been more aggressively, it is not correct to say that McClellan wasted 24 hours before attacking on September 14. The infantry fight at Fox's Gap opened less than 24 hours after McClellan first saw the orders. Cavalry and artillery opened sooner. In fact U. S. Cavalry pushed the Confederates back to South Mountain all day in September 13 (beginning before the orders were found).

I don't know where McClellan could have started the battle a few hours earlier. The fighting at South Mountain started around 7 am with infantry engaging at little before 9. The fighting at Antietam began on September 16 and resumed before dawn on September 17.

I still contend that Franklin could have attacked at Crampton's Gap earlier than he did one September 14.

I believe McClellan made mistakes but he was not incompetent as many would make him out to be.

I agree that McClellan was not incompetent, but I think his personal demons rendered his decisions incompetent. I have been corrected by other posters on this board that McClellan actually did try to move faster, but, to me, in the end it was not nearly good enough when facing Lee and the ANV.

To me though, on the day of the battle itself the delays in the Federal Attack resulted in the failure of the AoP to defeat the ANV. It was indicative of McClellan's generalship that even in this most climactic battle of his Career, little Mac could not bring himself to commit all his army to the battle. As usually he was fighting Not to lose, rather to win and that is how it was no more and no Less, and as a result the war endured almost another 3 years.


P.S. Did McClellan or his apologist ever accept responsibility for any untoward event during his tenure as CinC of the AoP?

 

[OpnCoronet]

It wasn't a surprise. Burnside got 90 minutes warning to the effect the AP Hill was crossing the river. The problem was, Burnside didn't do anything with that 90 minutes.

The troops from HF crossed in the rebel rear, at Boteler's Ford. They could not be interdicted.

Yes, with little mac, it was Never his fault for anything bad that happened.

 

[Andy Cardinal]

That's what intel and scouting is for.

Seriously, generals should always have staff and subordinates looking for information about the enemy. On something like this, cavalry patrols (large or small), scouts (IOW, spies), civilian sources and simple observation from across the river would have been able to tell McClellan a lot. The type of info Meade got on the night of July 2nd-3rd at Gettysburg (identifying the units that they had fought on days 1 &2) from his staff would have let McClellan know he had already fought most of Lee's army.

Unfortunately they intel Meade got was from a system implemented by Hooker, well after McClellan had been relieved. McClellan's

I agree that McClellan was not incompetent, but I think his personal demons rendered his decisions incompetent. I have been corrected by other posters on this board that McClellan actually did try to move faster, but, to me, in the end it was not nearly good enough when facing Lee and the ANV.

To me though, on the day of the battle itself the delays in the Federal Attack resulted in the failure of the AoP to defeat the ANV. It was indicative of McClellan's generalship that even in this most climactic battle of his Career, little Mac could not bring himself to commit all his army to the battle. As usually he was fighting Not to lose, rather to win and that is how it was no more and no Less, and as a result the war endured almost another 3 years.


P.S. Did McClellan or his apologist ever accept responsibility for any untoward event during his tenure as CinC of the AoP?

I would agree that McClellan often fought more not to lose than to win.

I really like David Welker's analysis of McClellan on his book about the cornfield. He argues that McClellan was incapable of making decisions s on the fly, and so when things did not go as he has planned he could bot adjust.

 

[Saphroneth]

So once again, McClellan had nothing to do with the surprise flank attack by Hill, it was Burnside's fault, or was it the Geography? It really is hard to keep track of all the excuses.

P.S. Are you sure of the line of march of the confederate reinforcements from
Harper's Ferry ?

Well, yes, I am, it's a basic feature of the geography:

Franklin can try launching an attack over the bridge from Harpers Ferry, but that doesn't get him in a position he can interdict the Confederate line of march.


As for the warning, yes, this is confirmed in primary sourcing. The signallers on Elk Ridge sent a message to Burnside (in response to a query of his) that there were enemy troops moving up from Shepherdstown, and some time later (at 3 PM) sent him a warning to "look out well on your left, the enemy are moving a strong force in that direction".

 

[Saphroneth]

How indeed, perhaps little Mac as Commanding General, should have made it his business to know. What, for instance, was Union Cavalry doing all this time and was he reading intel. reports from Washington?

Here's an interesting question relating to this, which is, what information could possibly have been gained from cavalry patrols and recon (and intel reports from Washington) that might have altered McClellan's plans?


Well, McClellan could not have known where McLaws and Anderson were on the morning of the 17th, because they moved from Harpers Ferry to Sharpsburg such that they arrived at Sharpsburg around dawn of the 17th. They moved overnight and consequently any cavalry recce that could have been done over the river would have been unable to detect the movement (as it could only be done by looking during the hours of daylight).

The movement of Jackson and Ewell was something that McClellan was (to my recollection) effectively aware of in the afternoon of the 16th, once the morning fog burned off. He may or may not have been aware of Walker, but that's a small movement.

The movement of AP Hill was spotted hours in advance.


As for intel reports from Washington... reading through the correspondence in the ORs there's not a lot, and what there is is sometimes like this:

Which is more a problem than a benefit, really. (At most this refers to Walker's force, but they were at Harper's Ferry by the 13th.)

 

[67th Tigers]

Yes, with little mac, it was Never his fault for anything bad that happened.

Show me his teleporters, or airborne division, and I'll concede the point. Otherwise, maybe you should maybe consult a map...

 

[GilbertFarney]

An intersting point about this is that in fact - had Harpers Ferry held out until the time Miles warned McClellan about, it would have been relieved. Franklin was on the march down the Pleasant Valley in the morning of the 15th, and Miles had said he could hold out until the evening of the 15th (when in fact he surrendered around 9AM).

It's an interesting what-if.

I agree completely. Had Miles shown some resolve and waited a day Mac would have gotten to him. There is evidence Miles could hear the cannon fire on South Mountain the day before he surrendered, too. Relieving HF would have also forced Lee to fully abandon Maryland as well. Halleck would have been declared a genius!

 

[GilbertFarney]

What is the advantage of staggering attack times on the two gaps? Hoping Confederate reserves will be directed to the first gap and unavailable for the second?



This is about the Second Bull Run campaign, correct?

I thought criticism of the AOTP showing a lack of haste involved the units coming from Washington, not the ones coming up from Aquia.



"Authority" is not the same thing as "responsibility."

McClellan was responsible for reinforcing Pope promptly even though it was a different army.

McClellan was responsible for saving the Harpers Ferry garrison whether he could give them orders or not, and regardless of whether he had specific orders to save them. Mac was aware of their peril, which was caused by the actions of his direct opponent (Lee and the ANV).

Yes, a staggered attack on the gaps was intended to draw Lee's attention and forces north so as to lessen the number of defenders facing Franklin at Crampton's Gap.

As for the authority vs. responsibility let's change the phrasing. Halleck did not give McClellan command over Harpers Ferry until Sept. 12. Up to that time McClelan had no authority or responsibility for the safety of the garrison. That fell to General Wool in Baltimore, commander of the Middle Department. McClellan warned Halleck multiple times before Sept 12, and as early as Sept. 5, that HF should be evacuated or the garrison stationed atop Maryland Heights. Halleck chose to do neither. Blame for the debacle cannot be reasonably laid at McClellan's feet.

 

[GilbertFarney]

Franklin has been criticized for showing no urgency or haste on the morning of the 15th.

Agreed, and rightfully so. How he ever thought McLaws outnumbered him 2-1 is a mystery. I think the man was a total failure as a corps commander.

 

[GilbertFarney]

If we suppose the lost orders had never been found, what would have happened?

Because Pleasonton and Stuart were already in contact and the 9th corps was already at and beyond Frederick, I believe the fight at Fox and Turner Gap would probably have unfolded similarly although probably not exactly the same.based on where different units might have been at dawn on the 14th.

McClellan did not expect a battle for the gaps to begin with. He believed the battle would be on the other side of the mountains. Lee also did not plan to fight in the gaps until he learned U. S. forces were beyond Frederick late on the 13th.

I am not aware that McClellan had any plans.for Crampton's Gap until after seeing the order. Franklin's attack was a direct result of the lost order.

My belief, based on my reading of Lee's plans is that there would still have been a fight at South Mountain if SO 191 had not been found, but it would not have involved as many men. It would have looked more like the fight at Braddock Heights/Hagan's Gap on Sept. 13 with Stuart defending the gaps vs. Pleasonton. Lee never intended to defend the mountain gaps. If HF had fallen by the 14th, which is what he hoped would happen, he would have pulled Hill's division back to Beaver Creek to meet with Longstreet. There they would await the forces detached to take HF and a battle would have been fough there sometime around the same dates as Antietam.

 

[GilbertFarney]

Again, you have to look at time and motion. Franklin needs to have his forces closed up at the foot of the gap before he attacks - he can't just attack off the line of march because then he's feeding brigades into a defensive position one at a time. You can gain an hour or two but you can't gain the several hours you need to advance down the Pleasant Valley on the 14th.

It's just a long way to go.


Do we know at what point the news reached McClellan that Harpers Ferry had been cut off? Given when that actually happened it might be that the Lost Order is McClellan's first confirmation that the enemy is actually doing that.

A plausible reason for the timing in ordering Franklin forwards might be that the Jefferson pass hadn't been taken yet; once the pass is taken (which was near sundown on the 13th) then it's an obvious thing to do to push Franklin over that pass, as it avoids the massive traffic jam at Frederick.

McClellan learned for certain about Harpers Ferry's fate on the morning of Sept. 14 when riders from Miles reached him at Frederick.

 

[GilbertFarney]

While I agree there are times McClellan could have been more aggressively, it is not correct to say that McClellan wasted 24 hours before attacking on September 14. The infantry fight at Fox's Gap opened less than 24 hours after McClellan first saw the orders. Cavalry and artillery opened sooner. In fact U. S. Cavalry pushed the Confederates back to South Mountain all day in September 13 (beginning before the orders were found).

I don't know where McClellan could have started the battle a few hours earlier. The fighting at South Mountain started around 7 am with infantry engaging at little before 9. The fighting at Antietam began on September 16 and resumed before dawn on September 17.

I still contend that Franklin could have attacked at Crampton's Gap earlier than he did one September 14.

I believe McClellan made mistakes but he was not incompetent as many would make him out to be.

Agreed, but one word as to timing. The sources suggest that artillery fire began around 9:00, with musketry starting about 30 minutes after that.

 

[GilbertFarney]

I am puzzled as to why McClellan didn't order Franklin to move until the morning of the 14th, instead of pushing him that evening over the Catoctins and set up an attack on the Gap earlier in the morning. Burnside and Hooker were already moving out of Fredrick into the Middleton/Catoctin Valley, and McClellan's order tells Frankling that McLaws/Anderson were in Pleasant Valley, so there is no tangible concern that Franklin couldnt have entered Middleton/Catoctin valley as well. Yes, an evening move. Yes, troops are tired. But, as evidenced by all of his messages, McClellan seemed to recognize the opportunity he had been given. Yet, he didn't push Franklin, despite his stated intention of wanting to split Lee in two.

I agree. McClellan should have wated no time pushing Franklin's command. Franklin even had a brigade already west of the Catoctins by the end of the day on Sept. 13. My guess is that he waited because he wanted Burnside's attack on the northern flank to launch first. This would drive Confederate reinforcements toward Boonsboro, opening the route to HF. That's the concept, at least. It is hard to imagine R. E. Lee doing similarly if put in Mac's place.

 

[Saphroneth]

McClellan learned for certain about Harpers Ferry's fate on the morning of Sept. 14 when riders from Miles reached him at Frederick.

I meant cut off, not surrendered. McClellan assuredly knew HF was cut off before then.

I agree. McClellan should have wated no time pushing Franklin's command. Franklin even had a brigade already west of the Catoctins by the end of the day on Sept. 13. My guess is that he waited because he wanted Burnside's attack on the northern flank to launch first. This would drive Confederate reinforcements toward Boonsboro, opening the route to HF. That's the concept, at least. It is hard to imagine R. E. Lee doing similarly if put in Mac's place.

Franklin may have had a brigade over the mountains, but you can't attack ten brigades (McLaws and Anderson were 1/4 of Lee's whole army) with one. Franklin begins the 13th at Urbana so getting to Jefferson is a significant chunk of marching in and of itself, and a lot of the delay in Franklin's actual attack is the need to close up - a common problem in period operational fighting, because if your leading edge reaches a point early in the morning it takes a whole day to close up around 30,000 men. This is actually the point of the European-style "corps" and the "wing" or "grand division" of about 30,000 men, since you can't reliably fit more than that down a road in a day.

 

[Saphroneth]

As an example of what I mean about the time delay caused by closing up and fighting, let's take AP Hill's march to Sharpsburg, described as "extraordinary" and "breathtaking" in some sources. This was a movement of about 10-12 miles (the distance by foot from Harpers Ferry to Shepherdstown) by 2PM (which is when AP Hill reached Shepherdstown), and AP Hill set off around 6 AM; that's more than one mile per hour but less than one and a half.

Using 1 1/2 miles per hour as a starting point, Franklin's leading edge going from Urbana via Buckeystown, Jefferson and Cramptons Gap to Sandy Hook MD would take a total of 19-20 hours of marching (this is 29-30 miles at 1 1/2 miles per hour). However, Franklin's column (fighting echelon only, just 6th Corps) would be:
7 batteries of artillery, gun plus caisson, assumed 4 guns per battery, total 56 vehicles at 16 yards per vehicle = 900 yards
12,300 infantry, 1,000 infantry in column of fours per 300 yards, = 3,700 yards
Total 4,600 yards, or 2 1/2 miles

And would take nearly two hours to close up (i.e. that is the time from when the first soldier in the fighting echelon reaches Burkittsville to the time the last soldier does).
Then there's the actual fighting, which historically took several hours.

You really start running up against the amount of hours of daylight there physically are on the 13th and 14th, even marching as hard as Hill's Light Division did and even assuming the column is in perfect order. (It's quite easy, particularly for new troops - and there were some in 6th Corps - for any delay to ripple back through the whole column and mean that the column "stretches out" past the intended minimum length.)


This is the cause of a lot of real world concerns about speed and mass. If you can take the pass earlier then you're improving speed (because you're reducing the length of the delay to the whole column) but you're doing so at the expense of mass (because you don't have enough time for all the troops to arrive).

 

[Jantzen64]

I agree. McClellan should have wated no time pushing Franklin's command. Franklin even had a brigade already west of the Catoctins by the end of the day on Sept. 13. My guess is that he waited because he wanted Burnside's attack on the northern flank to launch first. This would drive Confederate reinforcements toward Boonsboro, opening the route to HF. That's the concept, at least. It is hard to imagine R. E. Lee doing similarly if put in Mac's place.

I also don't understand how McClellan planned the strategy for the 14th. According to his order to Franklin, his intent was to break Lee in two, and yet, he only assigns one corps (plus one late-arriving division) to that key task? And the corps he selects is lead by a general who McClellan as slow and having "little energy"? If we are to believe McClellan's order to Franklin, then it's hard not to conclude that he did not give appropriate attention to what should have been the focus of the effort (Crampton's, not Turner's).

 

[Saphroneth]

I also don't understand how McClellan planned the strategy for the 14th. According to his order to Franklin, his intent was to break Lee in two, and yet, he only assigns one corps (plus one late-arriving division) to that key task? And the corps he selects is lead by a general who McClellan as slow and having "little energy"? If we are to believe McClellan's order to Franklin, then it's hard not to conclude that he did not give appropriate attention to what should have been the focus of the effort (Crampton's, not Turner's).

It's kind of a question of who else to use, really, given the positions that the corps are actually in and the operational terrain.

Basically you have two ways you can get troops past the Monocacy and the Catoctin passes to South Mountain - the northern route and the southern route.

The northern route is occupied by the troops heading to South Mountain. It's got a bottleneck at Frederick (only one road through town and no parallel route for several miles north or south) and is what most of the corps have converged upon, because Stuart retreated through the town late on September 12 and until that point there could have been Confederates there en masse for all McClellan could know - like there were until DH Hill left on the 11th.
Then there's another bottleneck which is the pass at Braddock Heights. It is, however, the route with the best roads, including the National Road and the Georgetown Pike (which merge at Frederick).


The other route, the southern route, is relatively unconstricted (as in, it's not a massive traffic jam with ~75,000 soldiers trying to fit down a single road) and that's what 6th Corps is taking, but the roads aren't as good, and it leads up to a single mountain pass (Jefferson Pass).


To get extra troops to Cramptons Gap, there are three possible ways to do this.

Way one: divert troops coming through the northern route.

This means having troops divert south after Braddock Heights (probably turning left at Middletown, between Braddock Heights and South Mountain). This means that you significantly delay the reinforcements for the column that's pressing up against South Mountain; if you divert 1st Corps then you're splitting up Burnside's wing and effectively expecting 9th Corps (which about the same sort of size as 6th Corps) to fight what - per SO 191 - might be Longstreet's whole force plus DH Hill's division, all of which are apparently at or around Boonsboro. 9th Corps has to handle that fight itself until all of 1st Corps has taken the turn at Middletown and 2nd Corps has come up behind 9th, which is a delay of several hours in the flow of reinforcements at Fox's and Turner's Gaps.


Way two: divert troops from the northern route to the southern route.

This means that you have 1st Corps (or whichever other unit) divert once they're through Frederick, and take Jefferson Pass instead. The result of this is that they end up stacked up behind 6th Corps, and can't begin to improve Franklin's situation until all of 6th Corps has arrived and closed up, as that's the earliest the reinforcement corps can provide a benefit. It also, again, means splitting up a wing, either Burnside's or Sumner's.


Way three: add extra troops to the southern route.

Again, they end up stacked up behind 6th Corps, and either you make the decision on the evening of the 12th (and if so you might actually avoid SO 191 being found in the first place - the whole reason it was found was that 2nd and 12th Corps were waiting for 9th and 1st to clear Frederick) or you have one of the 2nd/12th Corps detour around to become the tail end of the 6th Corps column.



Anything else means not merely splitting up wings but splitting up corps. As it was, 6th Corps had enough manpower once it had all arrived to take Cramptons Gap, so to make any kind of difference you need the same amount of men closed up sooner and so any solution that doesn't accelerate that is insufficient.