Not to get off topic but McClellans "strong objections" were that he needed 50,000 more men.
Um, when?
"Allow me to urge most strongly that all the troops of Burnside and Hunter together with all that can possibly be spared from other points, be sent to me at once. I am sure that you will agree with me that the true defense of Washington consists in a rapid and heavy blow given by this army upon Richmond.
Can you not possibly draw 15,000 or 20,000 men from the West to re-enforce me temporarily? They can return the moment we gain Richmond. Please give weight to this suggestion; I am sure it merits it."
(McClellan to Halleck, 26th July)
Burnside and Hunter is 21,000 men put together. At most he's asking for about 35-40 thousand, depending on whether you count Burnside and Hunter as not being "in the West" - and since in the past he's used Grand Aggregate when referring to his own army as well as that of the enemy, it might just be him asking for about 40 regiments.
Later, as his army got more healthy and the sick list shrank, his requests dropped and he was actually on the offensive again when ordered off the Peninsula.
In any case, there are three options:
1) McClellan wanted more men than would be necessary for a better general.
2) No possible number of men could have done the job.
3) McClellan could have done it if he'd had the men needed.
If (1) is the case - i.e. McClellan has enough men but not the skill or drive to use them - then the correct action by Washington would have been to
replace McClellan and not
withdraw him (preferably with one of his corps commanders, because only one of them thought they should be withdrawn and another felt they should stay and be reinforced if possible - the rest wanted to stay).
If (2) is the case, then it's no slight on McClellan that he tried anyway (and was on the offensive when ordered to give up the ground).
If (3) is the case, then of course Washington should have given McClellan whatever force they could. Just being there McClellan is forcing Lee to stay defending Richmond, because the CSA's industrial economy in large part
is Richmond (specifically, Tregedar, which includes the best rolling mill in the Americas and most of the machinery they took from Harpers Ferry).
It's worth noting, by the way, that Halleck (IIRC?) was
also saying Grant's Overland Campaign was a mistake and that he should be recalled with his army to defend Washington.
Plus ca change...
The big win for the Union if Lee fights for them is that Lee's not down south. Lee's big skill was that he was someone Jefferson Davis trusted who also happened to be a good general - take that away and the Confederate Army in the East doesn't have a consistent, good commander (IMO).