very insider-y Mark Halperin had been persuaded by the knowledge that Romney still believed he would be the best candidate in the field. It was a strong, plausible argument, and a lot of media outlets bit on it before former MA Gov. Romney announced that he would not be seeking the nomination.
Can't blame them though--it's way more likely that someone is going to notify the press that they are planning to be doing something than that they aren't. But by making the announcement this way, Romney ends speculation and I suspect makes room for other candidates, like Christie and Walker, to start doing their serious preliminary calculus. (This announcement likely has no impact at all on the decisions of Huckabee, Santorum, Jindal, Perry--you know. The guys Romney knew he was a better candidate than, already.)
Knowing one is an electable candidate isn't enough, though, and Romney made a good decision (one applauded by Jennifer Rubin, who was such a fan of Romney a scant few years ago) because running a national campaign is an arduous, costly affair, and it's a big commitment for not just a candidate, but their family, as well. And yeah, donors play a pretty big role in the equation, too; I'm sure that the move by former FL. Gov. Jeb Bush to meet with potential donors is what forced Romney to basically defecate or disembark the commode. I won't say the threat of a real competition scared Romney off--but I'd bet that realizing the effort needed to knock off someone with Bush's resources made the businessman in Romney recognize an unfavorable cost-benefit analysis to himself, the primary race, and the GOP.
Could he decide to return to the battlefield from his dark ship like a brooding Achilles turned to passion in the event of some crisis of party? Meh. Like Rubin, I still think I see the crack of the door open just a little. But it would have to be something seismic that picked off Bush, Walker, Christie--the plausible guys. He's been in races before and knows it isn't a whim.
The thing of it is--this puts name-recognition guy Bush in front-runner position, and I still can't say whether that's a good or bad thing. It's possible that he is too moderate for the 2016 Republican electorate taste. There might still be lingering "Bush fatigue". His last race was for FL Gov, and that doesn't tell me anything about what he'd do in a national race, and I can only speculate about the overlap the team around him might have with his brother's associates. It'll be, like, SC before I have a solid opinion.