McCain has stated that in general, the VP will be someone who agrees with his principles and priorities.
Despite the media's declaration that Rice is brilliant, I thought she had a low approval rating. I don't think she'll be the nominee and I don't think she wants it either.
McCain is stubborn. So I only think he'd choose Romney if his advisers were to persuade him to do so. They would have to persuade him of how Romney is a good speaker and could talk a lot about the economy. Romney showed in interview(s) this week that he'd be able to serve as a compliment to McCain's candidacy.
I don't expect Huckabee to be selected. McCain considers Huckabee's views on marriage and abortion to be too radical.
McCain likes Lieberman a lot. When McCain's campaign was in trouble during last summer, I had predicted that McCain might consider running as an independent with Lieberman. However, since McCain is claiming to be a "conservative Republican" on the campaign trail, I think he'd realize that he can't make that claim by picking him.
If Lieberman does get seriously considered, then I don't know why Giuliani wouldn't get considered. And between the two of them, I'm not sure why Lieberman would be more likely to get selected than Giuliani. Thus, I don't expect Lieberman to get selected.
So of the people on this list, I think that the governors of Minnesota and South Carolina both have the best chances. Also, the governor of Florida, Crist, also has a chance to get the VP nomination.
Has Rob Portman ever held a government position in addition to Budget Director?