I traced Obama's rise to the actress Jeri Ryan. She was married to a guy who was going to run against him in Illinois for Senate. But there was some kind of scandal where they got divorced because she said he wanted her to go to some sex club in Paris, so he dropped out.
Bush's rise could be traced to Bud Selig. After Fay Vincent was fired some wanted him to become commissioner. He was also being wooed to run for Governor. It was Bud who was pushing him for Commish but when George asked Vincent (who was a Bush family friend b/c he was a roommate of their uncle) he was told that if Bud was leading it, it was some kind of trap, he wanted the job for himself. So he ran for Governor instead.