Reader Tom Doran (twitter handle: @portraitinflesh) offers a sixth hypothesis explaining why Mitt Romney selected Paul Ryan to be his vice president, to supplement the five proposed below:
The more I think about it, the more the "pick Ryan because he's the best person to sell the Ryan plan" logic makes sense to me as Romney's rationale. Not that the plan itself makes sense - it's political leprosy - but Romney's calculus here has to be that he's already heavily committed to the plan and is himself the worst possible person to present it. Paul Ryan, as documented with hair-pulling frustration by Krugman, Chait and others, has successfully managed to play down the radicalism of his proposals in the eyes of the media. He comes across as a serious, pragmatic, decent, wonkish type rather than the Randian class warrior he is, which demonstrates serious political skill. Obviously I'd like to believe that this charade would be unsustainable under the glare of a total war campaign, but if he can pull the same trick on America that he's pulled on the Beltway, this could end up being very smart.