The Peninsula The Peninsula

[USS ALASKA]

Old Dominion University
ODU Digital Commons
History Theses & Dissertations
Summer 1991

John Bankhead Magruder and the Defense of the Virginia Peninsula, 1861-1862
Leonard W. Riedel Jr.
Old Dominion University

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ABSTRACT
The viability of the Confederacy depended on its ability to organize a government and military defense force. Two early concerns were the operation of Gosport Naval Shipyard and protection of the Confederate capital at Richmond. Poised between them was Fortress Monroe. With undisputed Union mastery of the Chesapeake Bay, Fortress Monroe was a constant reminder of the tentative security of these critical points. The man chosen to protect the Peninsula was Virginian, John Bankhead Magruder. Less than one year later, his efforts were denigrated by Commanding General Joseph E. Johnston who wanted to pursue his own strategic plan. Under constant stress, Magruder performed with alacrity. Although the Peninsula was evacuated in May 1862, Magruder did an admirable job of defense. Magruder's place in history has been discolored by perceived battlefield failures at Savage' s Station and Malvern H ill. These are an unfortunate footnote to an otherwise solid military career.

https://digitalcommons.odu.edu/cgi/viewcontent.cgi?article=1036&context=history_etds

Please use above link.

Cheers,
USS ALASKA

 

[Saphroneth]

So far as I can tell, the above work accepts the claim that Magruder was reinforced by "nearly 20,000 in the first week" (as of April 11, when Magruder states that the arrival of DH Hill's two brigades on that day means he has gained 20,000 reinforcements to his "old army" of 11,500 - the citation is to that message) which means that the evaluation of Magruder's command during the point he actually faced McClellan is fundamentally based on the idea that Magruder's 20,000 reinforcements all arrived in "the first week" (April 5-11 inclusive).
Early is similarly quoted as giving a 7:1 odds ratio as of when McClellan actually reached Magruder, without correction.

The problem is, this is incorrect. Of the reinforcements Magruder got by April 11, ca. 7,500 of them arrived before April 5, giving Magruder not less than 19,000 men as of April 5.

This doesn't mean Magruder was a poor commander, I hasten to add - just that the evaluation linked fails to correctly determine the force ratio and so any evaluation of what was going on around April 5 is based on a false premise.

 

[67th Tigers]

Early is similarly quoted as giving a 7:1 odds ratio as of when McClellan actually reached Magruder, without correction.

Early quotes McClellan's message wherein he tells Lincoln that when his whole force was up it would amount to 85,000 men, but the whole force was not yet up and he only had 53,000 men (43-44,000 effective) as "McClellan had 85,000 men."

Early remembered that Magruder told him he has 12,000, including the reinforcements from Wilcox etc., and Early brought 8,000 to make 20,000. This, of course, is contradicted by Magruder's statement on the 11th that he had 27,500 on the line with Early's arrival. Early clear made a mistake there.

Thus Early took 85,000 as McClellan's strength (i.e. roughly the strength ca. 19th April, when the last of Hooker's division arrived, but excluding some cavalry that hadn't or never would arrive) and compared against 12,000 to get the 7 to 1.

Thus, Early included large numbers of Federal troops that hadn't arrived, and excluded large numbers of rebel troops that had.

A more realistic calculation for the 5th-6th April would be to take Magruder statement of 27,500 after Early and deduct Early's statement of 8,000 to give 19,500, and compare to McClellan's statement of 53,000. About 2.7 to 1. Or take McClellan's estimate of effectives - 43,000 vs 19,500 = 2.2 to 1. This is slightly flawed since the first brigade from Early was arriving by the 6th, along with Cobb, but then Sedgwick's division was behind and didn't reach the line until the 6th.

However, a general statement of Magruder defended the line at roughly 2:1 odds on the 5th and so isn't unreasonable. Magruder certainly was outnumbered, but by a much smaller margin than claimed. The combat multipliers of the rivers and fortifications count for a lot...

 

[Saphroneth]

Quite. Magruder's skill on the Peninsula isn't deception (in multiplying his own numbers to disguise a huge overmatch) - it's in constructing a scheme of defences which canalized the Federal attackers into lanes that had been heavily fortified and could be defended with large numbers. Almost every conceivable feature to aid the defence was in place - covered flanks, heavy works proof against field artillery, inundations, continuous trenchlines, high parapets, enfiladed faces, good lateral communications, poor enemy lateral communications and land mines.

A Magruder who relied on deception to multiply his own numbers and disguise weakness would have been relying on a very specific reaction from his enemy, and would thus have been rather less impressive in terms of the actual work of defending than a Magruder who "simply" made the line very difficult to attack.

 

[67th Tigers]

Early's recollections are interesting. He concedes that the Warwick was an impossible obstacle to cross unless the dams were first cut to drain it, but that to cut the dams the rebel troops had first to be driven off. A Catch-22 situation.

The concern he had was the same as Magruder; that the redoubts and their curtain wall were "the most assailable point" and that they would have been untenable once the siege batteries were in place.

However, he then proceeds to lambast McClellan for not blasting these fortifications with his siege artillery immediately on contact, because the position was later reinforced and strengthened by adding additional lines of fortifications behind the main line. He ignores the engineering problems involved in getting these batteries up.

 

[Saphroneth]

Whether the batteries could have been accelerated is an interesting question - it basically amounts to second-guessing the work of engineers a bit more than 160 years ago. Given the available information in terms of expectations (six weeks, I think James Shields predicted during the evaluation) and the time taken to set up breaching batteries at the contemperaneous Fort Pulaski (two months) I don't think there's reason to think the batteries put up at Yorktown were particularly slow, since the complete timeline from reaching the Warwick to batteries in place was about four weeks; indeed, there's reason to think the work was quicker than we would otherwise expect.

 

[Nathan Towne]

It's an interesting question. The transports were unarmed, and hired less than six weeks before the movement.

The ships used were hired by John Tucker, and he supplied a list when a scandal broke regarding misappropriation of funds. The list does not include ships hired by anyone else (the minority used). For example, I know which ships 6 regiments of Richardson's Division went on, and two went on the large mail steamer Ocean Queen, which is not on the list. This is because the Ocean Queen was hired by the Sanitary Commission as a hospital ship, and pressed into one run as a trooper.

Irish Brigade - 2 regiments (69th NY and another) were transported in the large Ocean Queen, and the remaining one in the Columbia.

Howard's Brigade - The large Spaulding carried the 81st Pa and 61st NY. The 5th NH was split across two ships; the Donaldson (6 coys) and Croton (4 coys and the brigade baggage). The 64th NY did not go in the same convoy.

At least one large steamer on the list was not used as a transport, but transferred to the USN on 24th March to become a warship.

The steamers used to carry men ranged from some really large mail steamers, which could carry two regiments, down to small steamers which could carry half a regiment.

The real problem was horses. Schooners were used to transport horses, and a typical one carried ca. 40 horses or other animals. Consider a battery of artillery alone needs 3 schooners for her horses (and another few for her vehicles), or a cavalry regiment needs ca. 20 just for the horses.

As a note, only the first six divisions landed near Ft Monroe. Richardson's and Hooker's divisions landed at Ship Point after the army had reached the Warwick Line. The engineers built a new facility at Wormley's Creek during operations much closer to Yorktown which allowed easy supply of the army (even Ship Point was far enough away that supply was difficult), and that was where Franklin's division disembarked.

Nice find.

I can tell you how much the government was paying per day in contracting fees, but had never come across a list of all of the vessels utilized before.

 

[1SGDan]

A strong argument has been made by @Saphroneth and @67th Tigers that McCellen could of won the Peninsula Campaign but Lincoln pulled the rug under him.

Of course they did Mac is their hero and their pom pom waving never ends.

 

[leftyhunter]

Of course they did Mac is their hero and their pom pom waving never ends.

Which could be true. As a general rule battles are won and lost based on size and logistics.
Leftyhunter

 

[Belfoured]

Which could be true. As a general rule battles are won and lost based on size and logistics.
Leftyhunter

Sure. So try this exercise. How many troops did McClellan need to win the campaign? Assume his estimates of 150,000 - 200,000 for his opponent are accurate (that, of course, involves its own large number of problems that are irrelevant to this exercise).

 

[Nathan Towne]

Sure. So try this exercise. How many troops did McClellan need to win the campaign? Assume his estimates of 150,000 - 200,000 for his opponent are accurate (that, of course, involves its own large number of problems that are irrelevant to this exercise).

How many times on the Peninsula did he estimate the size of the Confederate force which the Army was facing, either to Washington, in intra-Army correspondence or in his personal correspondence?

The reason why I ask is simply that the size of the Confederate Army obviously changed dramatically over the course of the campaign and I would like to line up his estimates at each point, if possible.

 

[Belfoured]

How many times on the Peninsula did he estimate the size of the Confederate force which the Army was facing, either to Washington, in intra-Army correspondence or in his personal correspondence?

The reason why I ask is simply that the size of the Confederate Army obviously changed dramatically over the course of the campaign and I would like to line up his estimates at each point, if possible.

I haven't done a precise count. One would have to cover all three sources - and numbers in that range appear in all three. That's aside, obviously, from such estimates he made in periods before and after the April 1 - August 15 period. It's also aside from non-numeric statements such as the (non) arrival of Beauregard, etc.

 

[leftyhunter]

Sure. So try this exercise. How many troops did McClellan need to win the campaign? Assume his estimates of 150,000 - 200,000 for his opponent are accurate (that, of course, involves its own large number of problems that are irrelevant to this exercise).

My understanding is that towards the end of the Peninsula Campaign both sides were roughly equal in numbers. Ideally an army in the offensive especially in an era where no side as a technological advantage should have a three to one or better manpower superiority ratio. Lincoln was keeping troops at the fortifications in Washington DC and McClellan could of used them.
As one historian stated something to the effect McCellen is hard to place in history as he argued with Lincoln and defeated Lee. McCellen when he led the AoP had the best kill ratio of any AoP commander. On the other hand McCellen was an out and out racist. Also McClellan ' s troops loved him. So McCellen doesn't fit neatly in any boxes.
McCellen also took in Ambrose Burnside and his wife when his Burnside Carbine buisness went bankrupt.
Grant could hardly rub two nickles together when he resigned from the army vs McCellen was a successful railroad executive .
So McCellen is a complex character.
Leftyhunter

 

[Saphroneth]

Sure. So try this exercise. How many troops did McClellan need to win the campaign?

Surely this question doesn't actually need the later caveat you added to make it a complete question by itself.

Roughly speaking, of course, we know roughly what scale of reinforcements McClellan was asking for in May and June - it was 1st Corps. We know the scale of reinforcements he was asking for in late July - it was 9th Corps, plus any extra troops available if possible.

In both cases, this roughly corresponds to between 140,000 and 150,000 Union PFD passing through his army, which is on par with the strength the army was intended to have from the start when the Peninsular plan was first adopted (1st-4th corps inclusive as they were then, plus army-level troops).



In the Seven Days campaign as actually thought, the amount of reinforcements added before the start to the Union to make it a victory is not actually very large. It's enough troops to cover the approach over Tolopatamoy Creek, which Jackson crossed to unzip the Union position; without troops covering Tolopatamoy creek then the Seven Days means McClellan is forced further from Richmond, and with his existing strength McClellan could not cover Tolopatamoy creek without removing his assault concentration (that is, the amount of men south of the Chickahominy he was using to make progress against the Confederate defences).


In the Harrisons Landing period, McClellan was actually willing to advance without any reinforcements at all once he was told (for the first time) that he had all the troops he was going to get. This of course resulted in him advancing against an enemy which - once they called in Jackson's force to the north - would actually outnumber him, as Lee had outnumbered him in the Seven Days and had since got about 26 regiments as reinforcement while McClellan had got nine. But McClellan was willing to advance, and I conjecture that this is because Pope and Burnside were expected to exert enough pressure from the north that the chance of facing the whole force was unlikely.


So the amount of men that it would actually take McClellan to be successful in the Peninsular campaign, given the actual events of the Seven Days, is about what he was asking for and about the amount of strength that he was supposed to take in the first place (before Lincoln's modifications to what he could take, for various reasons).



The idea that we should calculate how many men McClellan would need, assuming that we take the highest of McClellan's strength estimates as read, is... an interesting one. But let's give it a go.



So the historical Seven Days in term of total regiments was

Confederate 215
Union 175


The addition of 1st Corps (two divisions thereof, roughly) would result in a situation where McClellan could successfully defend his northern flank while pushing closer to Richmond, as Lee's move to unzip the flank would not have worked. That means it becomes

Confederate 215
Union 200 (at 12.5 regiments per division average).


McClellan's estimate, at the highest, was generated from Confederate regiment count. That was a total of 252 at Richmond (an overcount of 36) at 700 AP per regiment, plus 20,000 men with Beauregard (basically another 28). So let's call it 280 regiments.

At a roughly 1:1 increase-for-increase basis, this would suggest that McClellan would need an extra 55 regiments over the "victory in the Seven Days" scenario. Burnside's 9th Corps is about 20 of these, so another 35 regiments need to be found from somewhere.

As of June 26, the actual strength of 1st Corps (the Dept. of the Rappahannock) in regiments is
King 12.3 plus cav
Ord 12.4 plus cav
Shields 16.5 plus cav
Doubleday and Geary 4

Total is about 45, so 20 over the amount accounted for above.

That leaves 15 regiments to obtain. At this point the force defending Washington is what would become 1st and 2nd Corps Army of Virginia, plus the defences of Washington as they were at the end of June.



That one last division is the problem... but then again, the 1:1 increase-for-increase is not necessarily correct. McClellan's defensive forces are dug in and can exploit the advantage of the defensive, while offensively what he needs is basically troops that can sustain attrition (as he's attacking into enemy defences which are deranged by heavy artillery fire).


Since we've already found enough regiments to reinforce McClellan to 240 regiments, which is several dozen over the amount that he asked for both at the end of July and during May and June (and which, I will note, is 56 over the amount that he actually had by the end of the campaign), I think this can best be ascribed as achievable.




Now, on the flip-side, how realistic exactly is it that McClellan might fight an enemy of a strength commensurate with his estimate?

Well, the 280 isn't really possible in reality - but the 252 isn't all that far off. By the end of July there were 243 regiments either at Richmond or in Jackson's force.




I've been sticking to regiments here because McClellan's estimates are derived from enemy regiment count, and because they're quantized. Sending 10,000 reinforcements could mean a lot of things, from 17 regiments (10,000 PFD at 600 per regiment) to 10 (notional 1-regiment-is-1,000-men, as Hunter attempted when asked for 10,000 men).




Bottom line is - McClellan was willing to attack Richmond through regular approaches on day one of the Seven Days, when his estimate was that the enemy in Richmond was stronger than his own force (he put them at 150,000 AP to his own 122,000, or possibly 170,000 if Beauregard was there).
He was also willing to advance on Richmond in late July/early August. That's a thing that happened.
The willingness of McClellan to attack an enemy he estimated as stronger is not in question.

So the amount that is necessary to actually win the campaign in the Seven Days is not the amount required to give McClellan more men than his estimate of the Confederates. It's not even the amount required to give him parity with his estimate of the Confederates. It's the amount required to give him the strength he needs to cover Tolopatamoy Creek without giving up his assault concentration or his coverage of Mechanicsville, and then enough to sustain his assault concentration.

That is achievable - and it's not far off what he was asking for in June. It's not far off what he was asking for, under different circumstances, in late July and August.

To whatever extent McClellan estimated the enemy as numerically stronger, given his actual actions it appears to have been roughly compensated for by his belief that he could successfully fight an enemy who had those greater numbers.

 

[Lubliner]

At the very beginning, in late October of '61 these were McClellan's estimates for an advance upon the southern front.
Column of active operations... 150,000 men and 400 guns.
Garrison of the city of Washington... 35,000 men and 40 guns.
To guard the Potomac to Harper's Ferry... 5,000 men and 12 guns.
To guard the Lower Potomac... 8,000 men and 24 guns.
Garrison for Baltimore and Annapolis... 10, 000 men and 12 guns.
Total effective force required... 208,000 men and 488 guns.

He then calls for an aggregate, present and absent of about 240,000 men should the losses by sickness not rise any higher than at present.
Lubliner.

 

[Nathan Towne]

Surely this question doesn't actually need the later caveat you added to make it a complete question by itself.

Roughly speaking, of course, we know roughly what scale of reinforcements McClellan was asking for in May and June - it was 1st Corps. We know the scale of reinforcements he was asking for in late July - it was 9th Corps, plus any extra troops available if possible.

In both cases, this roughly corresponds to between 140,000 and 150,000 Union PFD passing through his army, which is on par with the strength the army was intended to have from the start when the Peninsular plan was first adopted (1st-4th corps inclusive as they were then, plus army-level troops).



In the Seven Days campaign as actually thought, the amount of reinforcements added before the start to the Union to make it a victory is not actually very large. It's enough troops to cover the approach over Tolopatamoy Creek, which Jackson crossed to unzip the Union position; without troops covering Tolopatamoy creek then the Seven Days means McClellan is forced further from Richmond, and with his existing strength McClellan could not cover Tolopatamoy creek without removing his assault concentration (that is, the amount of men south of the Chickahominy he was using to make progress against the Confederate defences).


In the Harrisons Landing period, McClellan was actually willing to advance without any reinforcements at all once he was told (for the first time) that he had all the troops he was going to get. This of course resulted in him advancing against an enemy which - once they called in Jackson's force to the north - would actually outnumber him, as Lee had outnumbered him in the Seven Days and had since got about 26 regiments as reinforcement while McClellan had got nine. But McClellan was willing to advance, and I conjecture that this is because Pope and Burnside were expected to exert enough pressure from the north that the chance of facing the whole force was unlikely.


So the amount of men that it would actually take McClellan to be successful in the Peninsular campaign, given the actual events of the Seven Days, is about what he was asking for and about the amount of strength that he was supposed to take in the first place (before Lincoln's modifications to what he could take, for various reasons).



The idea that we should calculate how many men McClellan would need, assuming that we take the highest of McClellan's strength estimates as read, is... an interesting one. But let's give it a go.



So the historical Seven Days in term of total regiments was

Confederate 215
Union 175


The addition of 1st Corps (two divisions thereof, roughly) would result in a situation where McClellan could successfully defend his northern flank while pushing closer to Richmond, as Lee's move to unzip the flank would not have worked. That means it becomes

Confederate 215
Union 200 (at 12.5 regiments per division average).


McClellan's estimate, at the highest, was generated from Confederate regiment count. That was a total of 252 at Richmond (an overcount of 36) at 700 AP per regiment, plus 20,000 men with Beauregard (basically another 28). So let's call it 280 regiments.

At a roughly 1:1 increase-for-increase basis, this would suggest that McClellan would need an extra 55 regiments over the "victory in the Seven Days" scenario. Burnside's 9th Corps is about 20 of these, so another 35 regiments need to be found from somewhere.

As of June 26, the actual strength of 1st Corps (the Dept. of the Rappahannock) in regiments is
King 12.3 plus cav
Ord 12.4 plus cav
Shields 16.5 plus cav
Doubleday and Geary 4

Total is about 45, so 20 over the amount accounted for above.

That leaves 15 regiments to obtain. At this point the force defending Washington is what would become 1st and 2nd Corps Army of Virginia, plus the defences of Washington as they were at the end of June.



That one last division is the problem... but then again, the 1:1 increase-for-increase is not necessarily correct. McClellan's defensive forces are dug in and can exploit the advantage of the defensive, while offensively what he needs is basically troops that can sustain attrition (as he's attacking into enemy defences which are deranged by heavy artillery fire).


Since we've already found enough regiments to reinforce McClellan to 240 regiments, which is several dozen over the amount that he asked for both at the end of July and during May and June (and which, I will note, is 56 over the amount that he actually had by the end of the campaign), I think this can best be ascribed as achievable.




Now, on the flip-side, how realistic exactly is it that McClellan might fight an enemy of a strength commensurate with his estimate?

Well, the 280 isn't really possible in reality - but the 252 isn't all that far off. By the end of July there were 243 regiments either at Richmond or in Jackson's force.




I've been sticking to regiments here because McClellan's estimates are derived from enemy regiment count, and because they're quantized. Sending 10,000 reinforcements could mean a lot of things, from 17 regiments (10,000 PFD at 600 per regiment) to 10 (notional 1-regiment-is-1,000-men, as Hunter attempted when asked for 10,000 men).




Bottom line is - McClellan was willing to attack Richmond through regular approaches on day one of the Seven Days, when his estimate was that the enemy in Richmond was stronger than his own force (he put them at 150,000 AP to his own 122,000, or possibly 170,000 if Beauregard was there).
He was also willing to advance on Richmond in late July/early August. That's a thing that happened.
The willingness of McClellan to attack an enemy he estimated as stronger is not in question.

So the amount that is necessary to actually win the campaign in the Seven Days is not the amount required to give McClellan more men than his estimate of the Confederates. It's not even the amount required to give him parity with his estimate of the Confederates. It's the amount required to give him the strength he needs to cover Tolopatamoy Creek without giving up his assault concentration or his coverage of Mechanicsville, and then enough to sustain his assault concentration.

That is achievable - and it's not far off what he was asking for in June. It's not far off what he was asking for, under different circumstances, in late July and August.

To whatever extent McClellan estimated the enemy as numerically stronger, given his actual actions it appears to have been roughly compensated for by his belief that he could successfully fight an enemy who had those greater numbers.

I will note how McClellan's estimates of Confederate strength should now be understood as having been in Aggregate Present, which we don't have good figures for Confederate forces for most of the Peninsula campaign?

I agree with you that McClellan was continuing the push towards Richmond right up through the onset of the attacks on June 26th (or possibly decided by McClellan to abandon the effort for the time on June 25th, which has been discussed elsewhere).

What I simply do not understand is the fascination on the number of regiments and in formulating averages for regiment size in order to attain the size of the Confederate Army when we have much better material at our disposal. I have asked many times before where some of the regimental figures which 67th has put forward are coming from and have not received a response on that, as well.

 

[Saphroneth]

I will note how McClellan's estimates of Confederate strength should now be understood as having been in Aggregate Present, which we don't have good figures for Confederate forces for most of the Peninsula campaign?

I agree with you that McClellan was continuing the push towards Richmond right up through the onset of the attacks on June 26th (or possibly decided by McClellan to abandon the effort for the time on June 25th, which has been discussed elsewhere).

What I simply do not understand is the fascination on the number of regiments and in formulating averages for regiment size in order to attain the size of the Confederate Army. I have asked many times before where some of the regimental figures which 67th has put forward are coming from and have not received a response on that, as well.

It's because regiments are (1) what McClellan's estimates are based on, as in that is how the internal logic of the estimate operates, and (2) quantized. That is, whether a regiment was present or not is a binary detail - it is in fact a way of getting around the problem where we don't have good figures for Confederate force strength, and as a bonus it is a way that we can determine (for example) the rough fraction of Lee's whole army that he left in the Richmond defences.


Since we are generally talking about large total army sizes, the Law of Large Numbers should smooth out variations in regiment size, especially if we count on a per-company basis so we treat a battalion of 4 companies as 0.4 of a regiment and so on - meaning that as we evaluate a large number of regiments we should end up with an average that converges on the true average for Confederate regiments. It is then not formulating an average for regiment size, but simply using the Union average (which is based on data we actually have) and applying it to the Confederate regiment total to get an estimated equivalent Confederate strength in Union terms.

For this methodology to not work, then the Union and Confederate average regiment sizes would need to be significantly divergent.


Now, it is not the only way of estimating Confederate strength. In effect, we have three. One is the numbers from Tenney reported in Harsh (presented as Union-style PFD), one is the estimate based on regiment size, and one is the estimate based on officer ratio. These methods are all substantively independent, and notably the way the Confederate force average looks if the officer number approach is unreliable is different to the way the Confederate force average looks if the regimental-average approach is unreliable. The fact that both the regiment-size and officer-ratio approaches produce a higher number than the numbers in Tenney is, I think, sufficient information to conclude that the Tenney numbers (which are "PFD-style") are not high - and may be low.

The alternative is that the Confederate forces around Richmond are weaker per regiment than the Union (and thus have more officers per enlisted man) but that despite this Lee is still complaining that he doesn't have enough officers. This would be very odd, which means we should see it as unlikely.





If what you mean by regimental figures is "how many regiments", then to my understanding the answer to that is that it relies on the fact that 67th has been looking into this for a very long period of time and been taking and keeping notes! If there's a specific case then it may help to ask about that one specifically...

 

[Belfoured]

Surely this question doesn't actually need the later caveat you added to make it a complete question by itself.

Roughly speaking, of course, we know roughly what scale of reinforcements McClellan was asking for in May and June - it was 1st Corps. We know the scale of reinforcements he was asking for in late July - it was 9th Corps, plus any extra troops available if possible.

In both cases, this roughly corresponds to between 140,000 and 150,000 Union PFD passing through his army, which is on par with the strength the army was intended to have from the start when the Peninsular plan was first adopted (1st-4th corps inclusive as they were then, plus army-level troops).



In the Seven Days campaign as actually thought, the amount of reinforcements added before the start to the Union to make it a victory is not actually very large. It's enough troops to cover the approach over Tolopatamoy Creek, which Jackson crossed to unzip the Union position; without troops covering Tolopatamoy creek then the Seven Days means McClellan is forced further from Richmond, and with his existing strength McClellan could not cover Tolopatamoy creek without removing his assault concentration (that is, the amount of men south of the Chickahominy he was using to make progress against the Confederate defences).


In the Harrisons Landing period, McClellan was actually willing to advance without any reinforcements at all once he was told (for the first time) that he had all the troops he was going to get. This of course resulted in him advancing against an enemy which - once they called in Jackson's force to the north - would actually outnumber him, as Lee had outnumbered him in the Seven Days and had since got about 26 regiments as reinforcement while McClellan had got nine. But McClellan was willing to advance, and I conjecture that this is because Pope and Burnside were expected to exert enough pressure from the north that the chance of facing the whole force was unlikely.


So the amount of men that it would actually take McClellan to be successful in the Peninsular campaign, given the actual events of the Seven Days, is about what he was asking for and about the amount of strength that he was supposed to take in the first place (before Lincoln's modifications to what he could take, for various reasons).



The idea that we should calculate how many men McClellan would need, assuming that we take the highest of McClellan's strength estimates as read, is... an interesting one. But let's give it a go.



So the historical Seven Days in term of total regiments was

Confederate 215
Union 175


The addition of 1st Corps (two divisions thereof, roughly) would result in a situation where McClellan could successfully defend his northern flank while pushing closer to Richmond, as Lee's move to unzip the flank would not have worked. That means it becomes

Confederate 215
Union 200 (at 12.5 regiments per division average).


McClellan's estimate, at the highest, was generated from Confederate regiment count. That was a total of 252 at Richmond (an overcount of 36) at 700 AP per regiment, plus 20,000 men with Beauregard (basically another 28). So let's call it 280 regiments.

At a roughly 1:1 increase-for-increase basis, this would suggest that McClellan would need an extra 55 regiments over the "victory in the Seven Days" scenario. Burnside's 9th Corps is about 20 of these, so another 35 regiments need to be found from somewhere.

As of June 26, the actual strength of 1st Corps (the Dept. of the Rappahannock) in regiments is
King 12.3 plus cav
Ord 12.4 plus cav
Shields 16.5 plus cav
Doubleday and Geary 4

Total is about 45, so 20 over the amount accounted for above.

That leaves 15 regiments to obtain. At this point the force defending Washington is what would become 1st and 2nd Corps Army of Virginia, plus the defences of Washington as they were at the end of June.



That one last division is the problem... but then again, the 1:1 increase-for-increase is not necessarily correct. McClellan's defensive forces are dug in and can exploit the advantage of the defensive, while offensively what he needs is basically troops that can sustain attrition (as he's attacking into enemy defences which are deranged by heavy artillery fire).


Since we've already found enough regiments to reinforce McClellan to 240 regiments, which is several dozen over the amount that he asked for both at the end of July and during May and June (and which, I will note, is 56 over the amount that he actually had by the end of the campaign), I think this can best be ascribed as achievable.




Now, on the flip-side, how realistic exactly is it that McClellan might fight an enemy of a strength commensurate with his estimate?

Well, the 280 isn't really possible in reality - but the 252 isn't all that far off. By the end of July there were 243 regiments either at Richmond or in Jackson's force.




I've been sticking to regiments here because McClellan's estimates are derived from enemy regiment count, and because they're quantized. Sending 10,000 reinforcements could mean a lot of things, from 17 regiments (10,000 PFD at 600 per regiment) to 10 (notional 1-regiment-is-1,000-men, as Hunter attempted when asked for 10,000 men).




Bottom line is - McClellan was willing to attack Richmond through regular approaches on day one of the Seven Days, when his estimate was that the enemy in Richmond was stronger than his own force (he put them at 150,000 AP to his own 122,000, or possibly 170,000 if Beauregard was there).
He was also willing to advance on Richmond in late July/early August. That's a thing that happened.
The willingness of McClellan to attack an enemy he estimated as stronger is not in question.

So the amount that is necessary to actually win the campaign in the Seven Days is not the amount required to give McClellan more men than his estimate of the Confederates. It's not even the amount required to give him parity with his estimate of the Confederates. It's the amount required to give him the strength he needs to cover Tolopatamoy Creek without giving up his assault concentration or his coverage of Mechanicsville, and then enough to sustain his assault concentration.

That is achievable - and it's not far off what he was asking for in June. It's not far off what he was asking for, under different circumstances, in late July and August.

To whatever extent McClellan estimated the enemy as numerically stronger, given his actual actions it appears to have been roughly compensated for by his belief that he could successfully fight an enemy who had those greater numbers.

You make much of the very limited movement on June 25 which McClellan expressly limited in his orders - of course, that movement appears to be the fruits of his bold statement in a letter to Ellen that the big offensive would start on June 17 or 18. You also make much of the limited and unsuccessful foray towards Malvern during the first week of August, characterized by McClellan as a "reconnaissance". Your claim of McClellan's "willingness to attack" resembles the oft-repeated assertions by the General himself - promises that an assault rifle would be used, followed by the emergence of a water pistol.

By the way, nice job of subtly adding "AP" to McClellan's estimates.

 

[Nathan Towne]

You make much of the very limited movement on June 25 which McClellan expressly limited in his orders - of course, that movement appears to be the fruits of his bold statement in a letter to Ellen that the big offensive would start on June 17 or 18. You also make much of the limited and unsuccessful foray towards Malvern during the first week of August, characterized by McClellan as a "reconnaissance". Your claim of McClellan's "willingness to attack" resembles the oft-repeated assertions by the General himself - promises that an assault rifle would be used, followed by the emergence of a water pistol.

By the way, nice job of subtly adding "AP" to McClellan's estimates.

I don't think that McClellan ever entirely gave up on operations until at least June 25th. He continued to try to work the Army forward. I wouldn't go as far as you there.

I agree wholeheartedly with your second paragraph.

 

[Belfoured]

I don't think that McClellan ever entirely gave up on operations until at least June 25th. He continued to try to work the Army forward. I wouldn't go as far as you there.

I agree wholeheartedly with your second paragraph.

Your phrase "work[ing] the Army forward" is a more accurate assessment of the June 24-24 operation than demonstration of "willingness to attack". Entirely aside from the fact that this limited and cautious action took place a week after the bold prediction to Ellen had said that the offensive would begin, it's very helpful to read the orders/messages from McClellan on June 24 and June 25 for context. In that light the claim is, let's say, somewhat overstated.