Motivations for moving North
Lee who recently replaced Johnston was full of fresh new energy and was ready to cut off and destroy McClellan. Lee was looking for a dramatic victory that would end the war for good. A phrase that was heard quite after on both sides before a battle was to be fought.
One might wonder why Lee wanted to attack he had only half the men that McClellan had and if forced to retreat had no where to turn with his back to the Potomac River. However Lee knew that McClellan was a wimp who would not attack with full force and only used 2/3 of his men, even with Lee’s plans in his hands McClellan still managed to not strike and be victorious.
Still the question remained why would Lee push the army and attack Northern soil. Well for one he wanted to rally Maryland against the North and get them to succeed and join the Confederacy. In fact Rebels even sang to Maryland when marching into battle. Another reason is that Lee wanted to maintain his strategic initiative he gained from the seven days battle and the second Bull Run. Lastly Lee wanted to move the fighting out of the heart land of Virginia because the countryside was taking a toll from the fighting and the men no longer had supplies.
Lee wanted to move into Maryland or Southern Pennsylvania and live off the North’s food and fodder. All considered he still thought it was a good idea even with lack of men and supplies.