Paul Ryan seems to be the favorite, judging from the latest news stories. It makes sense to me because (1) Romney has still not persuaded Republicans of his conservative bona fides, and (2) Ryan is the darling of the GOP base. If chosen, he will energize the convention, as Palin did four years ago, the difference being that one of them is not a loose cannon. The downside is that his budget proposals will become a big fat target for Obama.
The other possible choices just don’t make a lot of sense. Chris Christie? RedState dismisses him as a moderate. Pawlenty is boring. Portman would be good if he could deliver Ohio, a key state, but RealClearPolitics’ average of recent polls has Obama ahead by 4.8 in the state. Condi Rice? She’ll remind the voters of the bad old days of the Bush Administration. CIA director General David Petraeus? This election will not be determined by foreign policy, defense, and security issues. That said, I would have chosen Petraeus.