I have always felt that if McClellan had acted on the information the same way Lee would have (immediately), he could have struck whilst Lee was still divided. But even then with little Mac believing that Lee had over 100,000 troops (I think it was closer to 30,000, if undivided), would he have been aggressive enough to make the move needed to destroy Lee?
I think not. McClellan suffered from the worst case of low self esteem...his correspondence with his wife has shown that he revelled in all the attention and respect thrown at him so quickly, that he seemed paralyzed by the possibility that a costly move on the battlefield would prove him less that a God....the very thing he thought he was....... a great example of someone believing his own press.
I wonder if he ever had a moment of clarity, and realized that he might have been able to save hundreds of thousands of lives, had he acted quickly and decisively.
Regarding the question of Lee's intentions above...here's my .02......I think, rather sophmorically, that the South was soooo close to getting the overseas recognition it needed, and if Lee was able to cement another victory on "northern" soil...it could have very easily resulted in the backing andd support form across the pond that the South so desperately needed and wanted..
Redmen