Allow me to allude to a few of the facts in the case. You and your officers at one interview estimated the enemy's forces in and around Richmond at 200,000 men.
At this time McClellan's actual estimate was:
180,000 AP during Seven Days (down from 200,000 as Beauregard's army had not shown up)
- 40,000 casualties inflicted (McClellan's estimate of casualties caused during Seven Days)
= 140,000 AP in Virginia (this including both Jackson's force and the force at Richmond).
Possibly this goes to ca. 150,000 AP due to the reinforcements during July.
Since McClellan's calculations pegged Jackson at 30,000 AP pre-Seven-Days (thanks to reports from other commanders facing Jackson) then it seems fair to assume McClellan's estimate of Jackson's force in July was about 25,000 AP and thus the force at Richmond was 115,000-125,000 AP.
I know one of his officers (I think Keyes?) thought the enemy force was larger than this.
The actual value was about 100,000 AP, plus Jackson's force (perhaps 20,000 AP). Jackson can of course be called in at any time to augment the Richmond defenders, but if he is then he's not able to menace the North.
General Pope's army covering Washington is only about 40,000. Your effective force is only about 90,000.
In fact Pope's army covering Washington was 60,000 PFD on June 30, or about 72,000 Aggregate Present, once you discount the two brigades en route to McClellan on that date.
McClellan's force was about 90,000 PFD, or about 110,000 Aggregate Present, excluding the Dept. of Virginia.
Note that Halleck is at best playing games with army definition numbers here, and at worst doesn't understand how AP differs from Effectives.
McClellan had started talking in Aggregate Present because that was what Lincoln used to refer to his own force (and because it's the kind of number his spies could more easily get, of course).
But you will reply, why not re-enforce me here, so that I can strike Richmond from my present position? To do this you said at our interview that you required 30,000 additional troops. I told you that it was impossible to give you so many. You finally thought that you would have "some chance" of success with 20,000. But you afterward telegraphed me that you would require 35,000 as the enemy was being largely re-enforced.
The telegram was actually sent
before the meeting, while Halleck was en route. It was waiting for him at his office.
The months of August and September are almost fatal to whites who live on that part of James River, and even after you received the re-enforcements asked for, you admitted that you must reduce Fort Darling and the river batteries before you could advance on Richmond. It is by no means certain that the reduction of these fortifications would not require considerable time, perhaps as much as those at Yorktown.
Oh, the inhumanity, it might take a
month to reach Richmond... that would mean McClellan reached Richmond in September 1862!
But all of your plans require re-enforcements, which it is impossible to give you. It is very easy to ask for re-enforcements, but it is not so easy to give them when you have no disposable troops at your command.
As of the time Halleck is sending this telegram, there are about 14,000 PFD afloat with Burnside at Fort Monroe. There are disposable troops right there amounting to close to 20,000 AP.
Of course, Halleck himself had during the Seven Days flat refused to release
any troops from his own department (numbering 215,000 AP in June 30 - he was asked for 25,000 or even 10,000 and rebuffed it) so there's a source of potential reinforcements right there.
Essentially Halleck is lying about "no disposable troops" - Burnside's force
is disposable troops. He's not been doing anything but wait at Fort Monroe to be sent up to join McClellan for the past month.
Talking AP, if those troops with Burnside are released to McClellan (along with the extra three regiments Hunter was willing to send once transport arrived, to bump it up to a full 20,000 AP) then the force strength becomes:
Confederate in Richmond ~ 100,000 (McClellan est. about 120,000)
Confederate with Jackson ~ 20,000 (McClellan est. about 25,000)
Union with McClellan ~ 130,000 (up from 110,000)
Union protecting Washington ~ 75,000 (Pope)
Not all of these forces convert quite so cleanly into Effectives as one another (chiefly because the Confederacy used black non-enlisted people on the logistics, while the Union handles them out of their Aggregate Present) but it's the sort of numbers one has to work with. If McClellan advances on Richmond and Lee calls in all his possible reinforcements the ratio is 1:1.15 Union:Confederate by McClellan's numbers, using AP (or 1.08:1 Union:Confederate using AP by the true numbers.)
As a comparison, the numbers on June 30 1864 are:
Confederate in Richmond ~ 70,000-75,000 (Dept. of Richmond is about 5,000 and may not be included in AoNV returns)
Confederate with Early - no good returns, but 15,000-30,000 was estimated at the time.
Union with Grant ~ 110,000 PFD (i.e. 120-130,000 AP)
Union protecting Washington ~30,000 (Augur)
If Lee calls in all his possible reinforcements and Grant advances on Richmond the ratio is about 1.33:1 Union:Confederate.
It's better to compare Effectives because the Confederates are more efficient at converting AP into Effectives, but using AP is an interesting exercise.