With a POD no later than April 13, 1861, have Edwin Booth (older brother of John Wilkes Booth, and widely regarded of the greatest American actor of the 19th century) become President of the United States or President of the Confederate States.
Southern Victory, then get Edwin into politics. maybe a senete bid in '66 or '67 then from that maybe a VP with Longstreet or Hampton. then running him self.