Romney wants the Presidency, and he's willing to fight. Hopefully Romney wants the Presidency badly enough that he'll be willing to operate as a conservative, to forestall TEA Party opposition in 2016.
Obama must have gotten a copy of Meghan McCain's Diary.
I think McCain honestly believed all the fawning ink written about him: how he was a moderate, “hands-across-the-aisle” sort of figure. A “maverick” in his own party. He figured that that if he didn’t say anything that could be construed remotely as “racist”, he’d win. And he kept his Senate seat, knowing he had power to return to if he lost. So he never even really tried. He spent more time telling folks what a “good guy” and “nice man” that Obama was than taking any clear stand against him.
Then he lost and JD Hayworth ran against him in a Senate primary and the gloves were off. Suddenly, McCain _really_ had something to lose (all that Senate power, seniority, and gravy) and he wasn’t about to let a radio talk show host come even close to beating him.
No doubt about Mitt, though. He wants it. Bad.
And, he needs obama and obama's record to run against.
He'd be beaten by almost any other potential demonrat other than Biden, especially by Hillary.
He needs obama.