User blog comment:The Milkman/Skyrim's Smorgasbord of Shortcomings/@comment-68.51.127.36-20120812035137/@comment-68.51.127.36-20120812145911

Well, Ulfric and Tulius are fighting over the White-Gold Concordate, which was made by the Thalmor. If they destroy the Thalmor, then there is no White-Gold Concordate, which means all they have to do is convene into a moot and make a new king.