Robert E. Lee, was a decorated veteran in the Mexican War, showing his skill at the battle of Cerro Gordo, it was his genius idea that brought a great victory. He isn’t a traitor. He loved the country U.S.A, and felt horrible that the people in the North were agressors and came and attacked them in Virginia.
Rather, he failed to act up to his father’s level. His father accepted the federal government commission to put down a rebellion. Lee shirked, then hid behind a state commission, then supported an army which illegally occupied US territory and had fired on US forces. He applied for pardon, thus admitting his wrong, which was not issued until after he died.