WI No CSA Invasion of Pennsylvania in 1863

What if, following Chancellorsville, the Confederate government decided to go with Longstreet's suggestions (IIRC) of reinforcing Vicksburg while staying on the defensive in Virginia, instead of Lee's proposed invasion?

I should note that while there are plenty who see this as a massive strategic mistake by the CSA, the decision does have its defenders (eg @usertron2020 has made a point on this board before about the ANV's food supply issues). That said, Vicksburg aside, the campaign may well have had disasterous diplomatic effects on the would be nation, which I've raised before:
A thought I've been having: in OTL, the Roebuck motion (the last serious attempt at moving toward British and French recognition of the CSA) was introduced June 30, and the debate on the motion began that day; while Britain would certainly have known of the invasion contextualizing the debate, the key event moving the events leading to this motion (backdoor diplomacy with Napoleon, etc) was the Confederate victory at Chancellorsville. However, the resumption of the debate was put off by the Palmerson government for several days, before, on July 10 (when Britain had could not yet have received word of the outcome at Gettysburg) moved to adjourn without finishing the debate on the motion.

I've been gleaming the notes on the Parliament debate, and it seems the invasion did in fact play a major role in keeping the motion from coming to a vote. Ferguson, who introduced the adjourning motion, remarked "The war, which up to the present time had been a defensive one on the part of the Southern States, now appeared to hare received the character of an expedition of the South against the North". And the Prime Minister explained it outright: "Events of the utmost importance are about to take place in America, and we may hear in the course of a few hours of results commensurate with the importance of those events—evidently, then, the present is not a proper moment to ask the Government to prejudice itself with respect to its free action."

My conclusion from this: if the Battle of Chancellorsville had not been followed up with the "Gettysburg Invasion", then events leading to the introduction of the Roebuck motion would still happen, only the motion would now be allowed to move forward. (I think that means it comes to a vote, but not 100% sure about Parliamentary procedure here.) What are your thoughts?
So what do you guys think? If we take the PoD itself at face value, how is the course of the war changed?
 
Britain isn't coming in at this late stage. I don't know about their probability at the beginning, but after Antietam it fell to zero
 
Britain isn't coming in at this late stage. I don't know about their probability at the beginning, but after Antietam it fell to zero
If by "coming in" you mean military intervention, then I won't dispute that here; but if it includes diplomatic recognition, which would have major implications in its own right, then I'd say the very existence of the Roebuck motion proves the probability was not zero, if nothing else.
 
Longstreet’s Corps is being sent on a fool’s errand if the CSA does this. Assuming Longstreet could have begun transferring troops west by rail at about the same time Lee began moving north for Gettysburg, his troops still could not have arrived prior to mid-late June. By that point, the numbers are overwhelming for Grant.

To emphasize how difficult it would be for Joe Johnston, even with Longstreet’s reinforcements, to dislogde Grant, it would need God’s fist to punch through Grant’s line. The approaches to Vicksburg by land are very finite. Grant ensured that all of these approaches had been fortified and manned. Johnston doesn't have the space and freedom of maneuver to make this scenario work. Grant's right flank was firmly anchored on the Big Black River; in addition, Grant positioned his forces so the rich farmlands in the area that could have fed any relieving Confederates armies seeking to operate there were not accessible to the Rebels. Grant had also prepared extensive defenses for a potential Confederate approach from the Mechanicsburg corridor from the other flank, which was the most practicable approach for Johnston's forces. Grant had learned the lesson of Shiloh and Holly Springs; he would not be caught unprepared here. To demonstrate what Grant could do: in response to a false alarm of an attempt by Johnston to advance, Grant was immediately able to concentrate 34,000 men under Sherman in strong defensive positions along his lines along the probable approach, and he left that force in place. That, at a bare minimum, is what an attack by Johnston would have faced. In Grant’s memoirs, Grant noted that he would have rejoiced if Johnston was foolish enough to attack him.

In the Eastern Theater, Hooker would still be in command of the Army of the Potomac, though I suspect that his time is limited, given his failure at Chancellorsville and poor relationship with Halleck. In the aftermath of Chancellorsville, the Army of the Potomac was not in a good enough condition to go on the offensive. The Army of the Potomac was bleeding men due to the expiration of the 9-months and 2-years enlistments. The Eastern Theater would remain a stalemate until the Army of the Potomac received enough reinforcements to resume their offensive operations.
 
You don't need to punch through Grant's lines. All that's needed is to block his foragers from taking stuff from the farms. That said, nothing stops Viscksburg from simply being stormed and overrun.
 
You don't need to punch through Grant's lines. All that's needed is to block his foragers from taking stuff from the farms. That said, nothing stops Viscksburg from simply being stormed and overrun.
Grant’s supplies are primarily coming from the river, those rich farmlands were within Grant’s lines. There was nothing the Confederates could do to stop Grant from keeping his army supplied.

Also, Vicksburg was not stormed, it surrendered after being starved out.
 
@Arnold d.c I know you said Longstreet's reinforcements couldn't arrive by mid to late June, but is it possible the Vicksburg Campaign could be affected prior to this? IIRC, Union victory in said campaign was very much not a sure thing, at least as late as early June.
 
Grant’s supplies are primarily coming from the river, those rich farmlands were within Grant’s lines. There was nothing the Confederates could do to stop Grant from keeping his army supplied.

Also, Vicksburg was not stormed, it surrendered after being starved out.

Forget the river. He can't surround the city and take all the farmlands at the same time. Grab those and avoid a direct confrontation.
 
Another aspect is, Lee is not given the time to 'live off the land' in rich PA for months and months. Instead he is forced to stay in picked over northern Virginia. This will make his supply situation much worse then in OTL. It also hands the strategic initiative entirely to the Union.
 
Another aspect is, Lee is not given the time to 'live off the land' in rich PA for months and months. Instead he is forced to stay in picked over northern Virginia. This will make his supply situation much worse then in OTL. It also hands the strategic initiative entirely to the Union.

Given how badly Gettysburg went for the South, this is probably a blessing
 
@Arnold d.c I know you said Longstreet's reinforcements couldn't arrive by mid to late June, but is it possible the Vicksburg Campaign could be affected prior to this? IIRC, Union victory in said campaign was very much not a sure thing, at least as late as early June.
Not at all, the fate of Pemberton’s army is sealed as soon as Grant is victorious at Chanpions Hill on May 16. While Grant was sceptical about reports of as many as 45,000 Confederates assembling under Johnston, he had called for reinforcements. Grant is not a man who is easy to shake, he would well understand the implications of Longstreet’s approach and Halleck, with his belief of force concentration, would do his damndest to ensure Grant got reinforced.
Forget the river. He can't surround the city and take all the farmlands at the same time. Grab those and avoid a direct confrontation.
You really don’t know much about the Vicksburg Campaign, do you? Grant’s army was already sufficient enough to do just that-siege Vicksburg and keep the farmland. Grant does not completely require the farmland, the river was sufficient in supplying his army, the farmland was useful in feeding his army, but more useful in denying the Confederate relief column any food.
 
You really don’t know much about the Vicksburg Campaign, do you? Grant’s army was already sufficient enough to do just that-siege Vicksburg and keep the farmland. Grant does not completely require the farmland, the river was sufficient in supplying his army, the farmland was useful in feeding his army, but more useful in denying the Confederate relief column any food.

If he has that many men, he has strictly more than necessary to maintain the siege line and a reserve for taking care of a relief party. Which someone (and I think it was you... I can't remember) just said there was only enough and he couldn't detach 3,500 men (I made up the number but someone said it couldn't spare any). That's a contradiction. Either he has the minimum required to maintain siege lines plus a force to deal with relief armies or he has enough to occupy the farms as well. Pick one
 
Not at all, the fate of Pemberton’s army is sealed as soon as Grant is victorious at Chanpions Hill on May 16.
On this point in particular -- even if the Siege of Vicksburg begins as OTL, wasn't it possible for the Confederates to cut his supply lines during the Louisiana Campaign? (It was my understanding that USCT and freedmen played an absolutely crucial role in this respect.)

Otherwise, point taken on Grant not being shaken and getting reinforcements.
 
On this point in particular -- even if the Siege of Vicksburg begins as OTL, wasn't it possible for the Confederates to cut his supply lines during the Louisiana Campaign? (It was my understanding that USCT and freedmen played an absolutely crucial role in this respect.)

Otherwise, point taken on Grant not being shaken and getting reinforcements.
While Milliken’s Bend and Young’s Point were supply points for Grant, they were not crucial for Grant’s supply operations, losing both of them would be an inconvenience but nothing more. Grant was more worried that there would be political fallout from the loss of these bases than any long-term military damage.
 
If he has that many men, he has strictly more than necessary to maintain the siege line and a reserve for taking care of a relief party. Which someone (and I think it was you... I can't remember) just said there was only enough and he couldn't detach 3,500 men (I made up the number but someone said it couldn't spare any). That's a contradiction. Either he has the minimum required to maintain siege lines plus a force to deal with relief armies or he has enough to occupy the farms as well. Pick one
I think we are now talking past each other. I never remembered stating that Grant could not detach forces. Let me start from the siege of Vicksburg: after Grant is repulsed on Mayy 22, he shifts to siege operations. He began to hear rumours about Johnston assembling a relief column for Pemberton, he starts to build fortifications around his siegeworks of Vicksburg (something like Alesia) and calls up for reinforcements from Halleck. In truth, Johnston’s force is too weak to do anything damaging towards Grant’s army. Grant’s lines received reinforcements in early June and was now capable of completely covering Vicksburg while maintaining fortifications on the approaches to Vicksburg. By the time Johnston had mustered a large force, Grant has starved Vicksburg enough for him not to worry about what the besieged could do and was itching to fight Johnston’s relief column.
 
What if, following Chancellorsville, the Confederate government decided to go with Longstreet's suggestions (IIRC) of reinforcing Vicksburg while staying on the defensive in Virginia, instead of Lee's proposed invasion?

The Confederate Government, meaning Jefferson Davis, as he was in effect his own SecWar, was not about to buck the wishes of Robert E. Lee, his absolutely most favorite military commander. Longstreet could make suggestions, but he would not be able to get his corps detached, except in the cold weather months, when the AotP was unlikely to conduct major operations.

Robert E. Lee was fighting for Virginia, not the Confederacy. Except for a brief tour of inspection of fortifications in South Carolina (long before taking over the AoNV), he spent the entire war fighting in Virginia, West Virginia, Maryland, and Pennsylvania. To be blunt, if he wasn't acting to defend Virginia, he just didn't seem to be terribly interested. Sending Longstreet's Corps, his strongest and best led, at a time when he has just lost his BEST ever commander (Jackson), during the very start of the Summer campaign season, would be for the Virginian Lee Unthinkable. Longstreet was thinking strategically, while Lee was showing his typical mastery of operations. But no one in the Confederacy seemed to grasp the elements of the Grand Strategic Threat the Union represented. Though to be fair, even if someone did (Johnston?), they lacked the forces to do anything about it.

I should note that while there are plenty who see this as a massive strategic mistake by the CSA, the decision does have its defenders (eg @usertron2020 has made a point on this board before about the ANV's food supply issues).

The massive food supplies (a wagon train 47 MILES LONG!) Lee garnered in Pennsylvania (even Maryland was no longer the land of milk and honey it was earlier in the war) enabled Lee to feed his army all the way through the rest of 1863 and into the Spring of 1864. But over the NEXT winter...well, THAT winter was one where even the most loyal veterans starting walking across No Mans Land to take the Union Oath of Loyalty. There comes a point where you go from a state of starving hunger to being truly starved. If not for the Gettysburg Campaign, I doubt seriously the AoNV would have survived the Overland Campaign. Rather, it would have been turned on its left flank either at Spotsylvania Courthouse or Petersburg. An army marches on its stomach, after all.

That said, Vicksburg aside, the campaign may well have had disastrous diplomatic effects on the would be nation, which I've raised before:

So what do you guys think? If we take the PoD itself at face value, how is the course of the war changed?

You're leaving a stripped Virginia defended by two lesser corps commanders (whose record up to this date give no real warning that they are now in over their heads) and a reckless cavalry commander prone to joyrides against an AotP Cavalry Corps that is not yet recognized by Stuart (and the rest of the AoNV) to be The Coming Man of the Union Army. The flower of the AotP infantry force was destroyed at Fredricksburg, the Artillery Corps is as superior to the Confederate gunnery as ever, but Stuart is heading for a nasty surprise that he never acknowledged to the day he died.

Granted, there is the issue of expiring enlistments. But there is still many enlistments good for another year, plus many militia (good and bad) coming up to defend their states. In the case of the New York State Militia, they were released to redeploy all the way to Gettysburg (the PA militia's performance was less impressive), not to mention the Unionist Maryland militia.

Vicksburg was important, but it was Gettysburg that Impressed. Sieges are one thing, but the Magnificent Lee being driven from the field by a newbie army commander? THAT impresses.

If Lee moves North w/o Longstreet, and its against Meade, its not likely that he's getting home. Stuart, yes. Parts of Hill's Corps, perhaps. But depending on when the rains come...Lee isn't going to get his "decisive victory" fighting against an officer who combines the best qualities of caution AND tenacity. Lee's victories so often depended on his putting "the scare" into his opponents, and/or getting them to do Something Stupid. He can't get that from George Meade.

Longstreet’s Corps is being sent on a fool’s errand if the CSA does this. Assuming Longstreet could have begun transferring troops west by rail at about the same time Lee began moving north for Gettysburg, his troops still could not have arrived prior to mid-late June. By that point, the numbers are overwhelming for Grant.

Add on all the inevitable de-railings and breakdowns you can expect traveling on a horrifically over-used Confederate rail system designed to support the economy of Slavery, not LOCs between cities!

To emphasize how difficult it would be for Joe Johnston, even with Longstreet’s reinforcements, to dislodge Grant, it would need God’s fist to punch through Grant’s line. The approaches to Vicksburg by land are very finite. Grant ensured that all of these approaches had been fortified and manned. Johnston doesn't have the space and freedom of maneuver to make this scenario work. Grant's right flank was firmly anchored on the Big Black River; in addition, Grant positioned his forces so the rich farmlands in the area that could have fed any relieving Confederates armies seeking to operate there were not accessible to the Rebels. Grant had also prepared extensive defenses for a potential Confederate approach from the Mechanicsburg corridor from the other flank, which was the most practicable approach for Johnston's forces. Grant had learned the lesson of Shiloh and Holly Springs; he would not be caught unprepared here. To demonstrate what Grant could do: in response to a false alarm of an attempt by Johnston to advance, Grant was immediately able to concentrate 34,000 men under Sherman in strong defensive positions along his lines along the probable approach, and he left that force in place. That, at a bare minimum, is what an attack by Johnston would have faced. In Grant’s memoirs, Grant noted that he would have rejoiced if Johnston was foolish enough to attack him.

Its difficult to imagine two outstanding Confederate Army generals less inclined to launch foolhardy assaults against entrenched positions than the cautious Johnston (1) and a nearly WWI-era thinker like Longstreet. (2)

1) Always maintain your forces in the face of the enemy! They can AFFORD great losses! We CAN'T!

2) Assaulting heavy field defenses is a loser's trick.

In the Eastern Theater, Hooker would still be in command of the Army of the Potomac, though I suspect that his time is limited, given his failure at Chancellorsville and poor relationship with Halleck.

Methinks Hooker has seen his future gone up in smoke. It wasn't just Halleck. The more that Lincoln et al learned about Hooker's "freezing up" during Chancellorsville...his days were numbered. He was lucky to last as long as he did.

In the aftermath of Chancellorsville, the Army of the Potomac was not in a good enough condition to go on the offensive. The Army of the Potomac was bleeding men due to the expiration of the 9-months and 2-years enlistments. The Eastern Theater would remain a stalemate until the Army of the Potomac received enough reinforcements to resume their offensive operations.

And yet, if the AoNV offers up a vacuum by taking the best third of their infantry force and sending them all the way to the Mississippi, even with expiring enlistments the AotP could have sufficient forces to take on the reduced AoNV quite handily.

Another aspect is, Lee is not given the time to 'live off the land' in rich PA for months and months. Instead he is forced to stay in picked over northern Virginia. This will make his supply situation much worse then in OTL.

The biggest reason (beyond promising that it would force Grant East) being to re-victual the army in PA using worthless CSA script. W/O that PA food, desertions in the Fall and Winter of 1863/64 will be far worse, and Meade's 1863 operations in Virginia might accomplish more than the humiliating retreats that they were.

It also hands the strategic initiative entirely to the Union.

Something unthinkable for Lee. He didn't stop launching offensives against the AotP until he'd lost his last two great corps commanders, Longstreet and Stuart. The last being the Wilderness. When he tried to launch a major attack on the AotP W/O these men (North Anna), the AoNV simply wasn't up to it. Allowing the AotP to escape a trap that previously would have resulted in them being hammered.

Given how badly Gettysburg went for the South, this is probably a blessing

Given the level of provisions gained from Southern-Central Pennsylvania, it kept the AoNV fed for a long time to come. The AoNV got pummeled at Gettysburg, but they didn't see it that way at the time. It was only post-Wilderness when it slowly started to dawn on the Confederates that their army just wasn't what it used to be anymore.

Not at all, the fate of Pemberton’s army is sealed as soon as Grant is victorious at Chanpions Hill on May 16. While Grant was sceptical about reports of as many as 45,000 Confederates assembling under Johnston, he had called for reinforcements. Grant is not a man who is easy to shake, he would well understand the implications of Longstreet’s approach and Halleck, with his belief of force concentration, would do his damndest to ensure Grant got reinforced.

Grant’s army was already sufficient enough to do just that-siege Vicksburg and keep the farmland. Grant does not completely require the farmland, the river was sufficient in supplying his army, the farmland was useful in feeding his army, but more useful in denying the Confederate relief column any food.

Control of the Mississippi, what with the use of the Ironclads, Tinclads, Timberclads, and the specialist Ram Ships (Force = Mass x Velocity squared), meant that keeping Grant in supply was never in question. It was more a matter of Grant denying the Confederates supplies in the region. One reason why his marches crashed into the Confederate capitol of Jackson before turning on Vicksburg.

If he has that many men, he has strictly more than necessary to maintain the siege line and a reserve for taking care of a relief party. Which someone (and I think it was you... I can't remember) just said there was only enough and he couldn't detach 3,500 men (I made up the number but someone said it couldn't spare any). That's a contradiction. Either he has the minimum required to maintain siege lines plus a force to deal with relief armies or he has enough to occupy the farms as well. Pick one

The latter.

However, a Confederate defeat at Gettysburg was not inevitable, highly likely, but not inevitable.

The best the Confederates could hope for at Gettysburg was, on Day One, to totally rout Buford's brigades, Reynolds' I Corps, and Howard's XI Corps before the remaining Union forces arrive later that day (Slocum's XII Corps and Hancock's II Corps) and that night. A moderate victory, (3) destroying two corps and forcing the AotP to fall back upon Meade's original choice for a defensive position: The Pipe Creek Line. (4)

3) Mind, OTL the Confederates certainly lost plenty of feathers themselves on Day 1. ITTL, those losses would be even worse.

4) The Pipe Creek Line being totally unassailable and unflankable.:eek: A shorter line, allowing a reserve, and an active rail line running (out of Confederate eyesight) parallel to and behind the entire Union force. For Lee to attack the Pipe Creek Line would require his entire army launching a frontal assault across wide open ground, with no way to pull off a flanking maneuver.

IOW, Pickett's Charge. Cubed!:eek::evilsmile::(:'(

OTL Meade had decided to follow Buford's/Reynolds'/Hancock's advice to try to hold Gettysburg, due to its LOCs advantages. But in a timeline where Lee "wins" they will take Gettysburg, but have the Union Army sitting on their southern flank. If Lee tries to go any further into Pennsylvania or Maryland, he puts Meade between him and home. With the fortifications of Washington standing in his way to the Southeast.

A genuine military victory on Days 2 or 3 for the AoNV is impossible. At least, if you disallow the Union Army getting the Criminal Stupids. For all the drama to be found in "The Killer Angels", Meade's work at playing fireman over those two days was stellar.

Indeed, Gettysburg wasn't guaranteed to happen at all.

If you look at the maps of the time, you'll note that there really wasn't anywhere else for the two armies to go, short of Meade choosing to stay at Pipe Creek, and Lee choosing to stay spread out over the width and breath of South-Central Pennsylvania. (5) It may well have been a sign of his being new to command that he allowed his first thoughts on the subject of where to fight to be changed. After all, Reynolds was the man Lincoln first offered command of the AotP to before Meade. He may have found it impossible to say no to Reynolds. And Hancock DID confirm to Meade that Gettysburg was the better place to fight. (6)

5) Every other direction for Lee pointed him to places he couldn't reach, due to topography and the fact that he couldn't allow Meade to get between him and home.

6) Personally, I disagree. But by then, the AotP was committed to fighting at Gettysburg.
 
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So overall, it's damned if you do, damned if you don't situation for Lee and the Confederacy?

Makes sense.
Not necessarily, Lee’s invasion of Pennsylvania is only truly doomed when Lee decides to continue fighting at Gettysburg at Day 2. By that point in time, Lee had already collected a good amount of supply for his army and crippled the Union I and XI Corps. By deciding to continue fighting at Gettysburg, where the terrain heavily favours the defenders, Lee has effectively lost the campaign.

Lee has an unfortunate habit of fighting a battle whenever the opportunity presents itself. It backfired badly at Antietam (10,000 Confederate soldiers became needless casualties) and at Gettysburg.

The option to try to save Vicksburg is a fool’s errand. Between the choice of invading Pennsylvania and reinforcing Vicksburg, the invasion of Pennsylvania was clearly the better option.
 
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