Actually,
if you want it real screwed up, you should have Lee lead the Confederacy to victory and then have it eventually rejoin the union.
The experiment in States' rights would have failed eventually--the articles of the confederation proved that--and it would pull a major change on American history.
Lee was from Virgina, after all, and everybody knows that the South had the best generals because all of the top military academies were in the South.
Save your Confederate money, boys! The South will rise again!
Laura