In the slow news months of summer in a general election year, the press invariably begins speculating on who the VP nominee will be, which has the potential to deflate the announcement if they guess right.
So to distract the press, the campaign dangles red herrings for the press to bat around. Usually, the "dangles" are more of something than the presumptive nominee wishes to actually have--too conservative, too liberal... too goddamned crazy. The dangle is supposed to present the candidate as open-minded and mindful of the minority party interests.
But now I'm not so sure. In another post I pointed out that there are numerous entities which can claim to have a say in Romney's pick for VP: Romney himself, the Mormon Church, the billionaires who bought his campaign (perhaps each one individually), knuckle-dragging teabaggers, and Ron Paul.
Some of those entities, I think, will outright refuse any female candidate, any person of color, and anyone with the last name of "Paul." So my usual guess is that the vetting of Bachmann is a "dangle" which may actually be tipping us off to the fact that a female will not actually be seriously considered.
Personally, I think Jon Huntsman is the only guy they can settle on, but it's a guess of elimination based on no actual evidence except Huntsman's total silence. So don't bet real money on him.
But here's the thing: I've never seen a candidate go completely underwater before the convention like Romney has--McCain was close, but nothing like this. So he has to do something different and Romney may realize it. He's not particularly creative, either, so "doing a Palin" may be an actual, totally idiotic, plan.