Santorum support will got to Gingrich, if it was going to go to Romney it would already have done so.. Romney has been at 30% or whatever it has been since day one.
You are right, folks going to Santorum are folks who may not like everything to do with Gingrich, but sure aren’t going to Romney, given a choice between the two, the overwhelming majority will return to Gingrich... which is where most of them came from in the first place. Already see it happening in SC.
Santorum basically is just the last guy standing for this boomlet ideological purity crowd to jump to, but they will soon see he’s not as pure as they want him to be, nor up to the task. Just as Bachman, Perry, and Cain before him. Santorum is at best a VP candidate, and given how hated he is in PA, that makes him actually being selected as one difficult, but ability wise, that’s where he is, he’s VP Tier at best, not big show tier, not even close.
If Santorums the nominee, Obama’s machine will run him over, and pull out a squeaker, but pull it out none the less. Santorum gets painted as unsafe/radical, you get a 3rd party to peel off a few percent and you get Obama II with a plurality.
Your theory is as plausible as mine. From what I see, though, Romney is daily becoming more palatable to many Not Romney voters and Gingrich is becoming increasingly unlikeable.
The more steam Romney picks up, the more likely it is, in my view, that many (not all) of the former Not Romney/Gingrich voters will go to Romney or cast a protest vote or sit this one out.
I just don’t see a path for Gingrich to win, or win back, many more votes at this time or with the tactics he has chosen, nor with the lay of the political landscape against him.
But one of is — maybe — is right! ;)