Here's why Romney backed off

Mitt Romney didn't have much luck kissing babies
at a 2012 campaign stop in Macomb County. MLive photo

One hour before Mitt Romney's conference call this morning, where he announced he will not make a third White House run, the folks at NBC News pretty much nailed it in terms of laying out the reasons why the GOP's 2012 nominee might make a surprise exit.

Here's what they reported at 10 a.m.:

Your big political news of the day is that Mitt Romney plans to hold a conference call at 11:00 am ET today with his closest supporters to discuss his 2016 presidential intentions, MSNBC's Kasie Hunt confirms. No one knows for sure what Romney will announce, but the hunch coming from Romney World is that the former Massachusetts governor is going to give it another try. But here's why Romney has to make up his mind now: The ground underneath his feet is already beginning to crumble. Just yesterday, we learned that Romney's top Iowa strategist in 2008 and 2012 -- David Kochel -- is set to be Jeb Bush's campaign manager. We also learned, via the AP, that some of Romney's past donors are jumping aboard the Jeb Train. And get this: We can tell you that folks whom Romney has INVITED on this call are already planning to work for Bush. (Remember, a lot of these people have been connected to the Bush World longer than to Romney.) So if Romney is going to do this, he needs to make a clear statement ASAP (and don't be surprised if it comes in the form of a PAC or other committee). It's not too dissimilar for what Jeb had to do a couple of months ago: convince skeptical politicos and donors that you're actually in the race.
From 2012 GOP nominee to "even footing" at best
When it comes to Romney possibly losing former advisers and donors to rivals, keep this in mind: Romney is going from being the GOP's general-election nominee -- with most of the party fully behind him -- to someone who's making a THIRD primary run. So you're bound to have these kinds of defections. As political scientist Jonathan Bernstein puts it, "The best case for [Romney] at this point is that he's on more or less even footing with several other candidates." Now, you can certainly win your party's presidential nomination on even footing. But Romney also won't be as strong right now as he was in the summer/fall of 2012 -- it's just a fact.
Measuring Romney vs. Jeb
By the way, here are Romney's and Bush's fav/unfav from our most recent (Jan. 2015) NBC/WSJ poll:

• Overall for Romney: 27% positive, 40% negative
• Overall for Bush: 19% positive, 32% negative
• Among Republicans for Romney: 52% positive, 15% negative
• Among Republicans for Bush: 37% positive, 15% negative

Bottom line: Both men are unpopular overall (and have actually lost ground since our previous polling); Romney is more popular than Bush among Republicans; but Bush also has more room to grow.