An interesting , as a aside, article. 

Might I say of General Lee that the 'North' wanted him to lead their armies into the 'South', Lee being regarded as the best of all the Generals, both after the Mexican War and as Commandant of West Point. He declined primarily because he was from the South and defending, in effect, his home and Homeland. A difficult decision. 

The South's Armies lost because they ran out of men and supplies rather than poor generalship.