"Lee Surprised by McClellan's Speed"

[Andy Cardinal]

The timing of the Snavely's Ford crossing (as far as I'm aware) is that it comes after the bridge is taken.

My understanding is more or less simultaneous. But yes, Federal artillery placement played a big role in the end.

As did Confederate artillery on Cemetery Hill and the Harper's Ferry road ridge. They are the main reason Burnside's attack failed. They impacted the attack before AP Hill even got there.

 

[Saphroneth]

My understanding is more or less simultaneous.

I mean in terms of that the Confederates withdrawing from the bridge meant that the unit covering Snavely's Ford also pulled out and revealed it.

 

[Saphroneth]

There is something I actually want to point out with respect to Antietam, which is that generally speaking the discourse around Antietam revolves around whether there was an opportunity missed to destroy Lee's army.

Whether that was actually within the realm of plausibility I'm not sure about. The attacks on both flanks are certainly material for a battle of annihilation, but I suspect that if the Confederate army was in imminent danger Lee would presumably have opted to block Burnside's advance with everything he could spare and attempted a withdrawal by stages. This scenario would doubtless inflict heavy losses on the Army of Northern Virginia, but as we know from Second Bull Run even a fought-out army hit by surprise in the flank can put together a series of interim delaying actions that can facilitate a retreat. My count is that about half of Lee's brigades (as of the end of the day, that is) capable of at least some further defensive action - I'm counting that as the units that were at most in long range firefights - and so under those circumstances I think delaying actions are possible and that quite a lot of Lee's army does in fact get away. Though their morale would be shot and so the AoNV would be significantly weakened for further campaigning.

But it's not really what anyone might predict looking at the situation as of September 2!

 

[Rebforever]

When I read Hartwigs book McClellan did a fine job moving his army to Antietam. He made the right moves in taking the mountain in front him. I am not sure when he got all miscombobalated with his orders after that. Maybe he ate too much food when he got over the mountains.

 

[Andy Cardinal]

There is something I actually want to point out with respect to Antietam, which is that generally speaking the discourse around Antietam revolves around whether there was an opportunity missed to destroy Lee's army.

Whether that was actually within the realm of plausibility I'm not sure about. The attacks on both flanks are certainly material for a battle of annihilation, but I suspect that if the Confederate army was in imminent danger Lee would presumably have opted to block Burnside's advance with everything he could spare and attempted a withdrawal by stages. This scenario would doubtless inflict heavy losses on the Army of Northern Virginia, but as we know from Second Bull Run even a fought-out army hit by surprise in the flank can put together a series of interim delaying actions that can facilitate a retreat. My count is that about half of Lee's brigades (as of the end of the day, that is) capable of at least some further defensive action - I'm counting that as the units that were at most in long range firefights - and so under those circumstances I think delaying actions are possible and that quite a lot of Lee's army does in fact get away. Though their morale would be shot and so the AoNV would be significantly weakened for further campaigning.

But it's not really what anyone might predict looking at the situation as of September 2!

I agree that the likelihood of destroying Lee's army was slim to none. That just didn't happen in any battle outside of Nashville, except when the defender was forced to surrender.

Burnside's attack was a threat to the ford, but even if AP Hill hadn't arrived when he did, the 9th corps wasn't strong enough by itself to seize it and hold it.

 

[Andy Cardinal]

When I read Hartwigs book McClellan did a fine job moving his army to Antietam. He made the right moves in taking the mountain in front him. I am not sure when he got all miscombobalated with his orders after that. Maybe he ate too much food when he got over the mountains.

I don't believe he got discombobulated with his orders. I am not sure that he reacted too well when his plans didn't go according to plan, but many (most) commanders had that problem. Hooker for one. But I think it's easier to find those who did react well on the fly than name everyone who did not.

 

[Saphroneth]

I agree that the likelihood of destroying Lee's army was slim to none. That just didn't happen in any battle outside of Nashville, except when the defender was forced to surrender.

Burnside's attack was a threat to the ford, but even if AP Hill hadn't arrived when he did, the 9th corps wasn't strong enough by itself to seize it and hold it.

Even at Nashville Hood's army still exists afterwards. It takes heavy casualties (as a % of its total strength), but a recognizable version of Hood's army gets away. It falls apart from desertion afterwards.

And yeah, I don't think you can block the exit of the AoNV with 9th Corps. Interestingly if you know in advance that Hill will be called to Sharpsburg you could probably call Couch to Antietam instead of Franklin, and then have Franklin basically "chase" AP Hill and seal off the ford that way - but that really does take hindsight.

 

[Saphroneth]

I don't believe he got discombobulated with his orders. I am not sure that he reacted too well when his plans didn't go according to plan

My read on what McClellan is doing is that the reason he can't compensate for the things going wrong with 9th Corps in the morning is that he is fundamentally busy with the crisis on the right flank. The two things are happening at about the same time - Mansfield is down and Hooker wounded by about 9AM (which is the time point at which the attacks on the Rohrbach bridge start) and then there's the West Woods disaster; it's not until 6th Corps is deploying that the situation is truly stable, so it's a long period of chaos. This is a form of crisis management that takes McClellan committing an entire corps (6th) in addition to the 2nd Corps division that had been sent over recently, that being Richardson (and the crisis is that Lee commits essentially his whole reserve in his own right).

It's once the crisis on the right is over that McClellan checks on Burnside. I should also flag up here that alone of McClellan's corps commanders not called "Fitz", Burnside has an actual record in independent command (and for that matter his corps did okay at South Mountain) so I think letting "Burn" handle himself while the crisis is going on is understandable in that light.

 

[Andy Cardinal]

It's easy to forget how well thought of Burnside was in September 1862 by almost everyone, or that he was arguably the second most successful independent commander of the war so far. My read on him is that he really missed Jesse Reno. The command situation was a problem (without going into it too much) and I am not sure that the Burnside/Cox dynamic was very functional. According to Cox, Cox was great, but I am not so sure, although I believe he ye was competent. Cox was no Reno though.

Obviously Reno died too soon to know what he was really capable of, but there is no doubt, if you read about the NC campaign especially, how much Burnside relied on him. You might go so far as to say that Reno was the brains of the outfit.

Regarding McClellan and plans not going to plan, I agree to the extent that the crisis on the right inaugurated by the West Woods fiasco, overtook any plan that might have been in place.

 

[Saphroneth]

My rough read on the situation as of the early afternoon is that, from McClellan's point of view, Burnside now has the bridge and he can feed 9th Corps over it and get them attacking. In addition to that actual attack, it forces Lee to react; if Lee has at least enough strength available facing south or in reserve to fight Burnside head-on, then when Burnside advances he will have to have them doing that. At the same time he must hold the centre facing Sykes, and in the north McClellan has the assets to potentially make another attack. That is the threat posed by Franklin's corps.

McClellan can reinforce one of those threat axes that he is presenting Lee with with Morell's division (only). And he has to be quite sure that any attack he launches will at least cripple Lee's offensive capacity - Burnside could at least fall back to the bridge, but if he exhausts 6th Corps then 2nd Corps behind them (for example) could really be in for it if Lee advances.

However, until McClellan does commit Lee has to hold a front line (as noted) and so those forces can't be facing south against Burnside.

In that light I think McClellan's working assumption is that Lee's nearly out of reserves and under severe strain. McClellan ultimately decides to commit Morell on the right rather than the centre, but either way the basic plan seems to be to attack all along the line with all the fresh troops he has left so long as he can attack all along the line. (Sykes' division links up with 9th Corps, at least by my understanding, before AP Hill caves in 9th Corps.)

Basically under these circumstances so long as at least one of those three attacks works, so long as the other two do not collapse before then the result is a Union victory (albeit maybe not very decisive).

But as soon as one of the attacks fails (9th Corps, and it seems to have collapsed quite suddenly) the dynamic is no longer really in place. The assumption that Lee is nearly out of reserves is suddenly much more tenuous, and importantly anything that was previously facing south can be reoriented to face north.
I think McClellan probably knew AP Hill (or a body of troops that we know was AP Hill) had arrived, and we actually to my recollection have records of Burnside/9th Corps being warned by the signals guys. So whatever Lee had facing south at about 12:30 can now be reoriented to face north; the situation is significantly worse for an attack.

Worse, at that point there's guns firing to the northwest. We know that's Stuart's flanking move at New Industry being stopped, but McClellan doesn't yet.