"Antietam/Sharpsburg?"
Much of MD's population was more slanted towards sympathy for the Confederate cause, than the Union cause.
Incorrect. Lee expected to augment his forces with Maryland pro Confederate sympathizers, which largely did not happen.
Yep. Lee didn't get the bump in support that he was hoping for when he moved into the Sharpsburg area. Perhaps there was more pro Confederate support on the Eastern Shore area? Lee didn't get trounced at Antietam either. It was a pretty even fight. Lee did return to Virginia after the battle, giving the Union a tactical victory. Both armies performed pretty darn well at Antietam, IMHO.
