That is a hypothesis, but it has no facts to support it. Multiple polls show that Santorum in Florida took more votes from Romney than Gingrich, so he actually helped -- not that it mattered, even if every Santorum voter voted Gingrich Gingrich would still have lost.
I've explained elsewhere how it could well be that Newt can't get above a certain support level, so he'll never win, but his presence makes it impossible for people to consider Santorum as the alternative.
Then two polls came out, in Missouri and Ohio, that illustrated the point. In Missouri, the poll was (from memory) Gingrich 26, Santorum 24, Romney 20. But Gingrich-Romney was only +1 (Romney got 5% closer with Santorum out), while Santorum-Romney was +13 for Santorum. So while Gingrich is nominally in the lead, it's only because Santorum is there. Remove Santorum, it's a toss-up. Remove Gingrich, and Santorum runs away with it. In Ohio, similar results. Gingrich-26, Romney-25, Santorum-22(?). In Ohio, if Santorum quits, Gingrich is ahead by +3, so he benefits marginally by Santorum dropping out, but is still within the margin of error. But if Gingrich, in the lead, drops out, Santorum beats Romney by +8, and easy win. So there is two cases, yes just polls, but which illustrate how if the 1st-place guy quits, the 3rd-place guy beats the 2nd-place guy by much more than the 1st-place guy does if the 3rd-place guy drops out. I'm not telling Gingrich people not to support Gingrich, or telling Gingrich to drop out. I'm saying there is no evidence that Santorum dropping out will help Gingrich, and a lot of polling data to suggest both that it would HURT Gingrich, and that Gingrich can't beat Romney. Then there are the national polls which show that while Santorum is within single digits of Obama, Gingrich loses to Obama by 14 points. Again, it's a poll, not fact, but polls are all we have to argue that Gingrich is the "best candidate". I just don't see Gingrich proving himself the best candidate. In the past month, he's made at least 3 left-wing attacks, yes against Romney, which we like, but from the left, not the right. He has been criticized TWICE by the Club for Growth. He had to pull an ad after being criticized by Marco Rubio. He's been attacked harshly and unfairly, but whether fair or not, it has hurt him, his negatives are high, his support is weakened. Can he recover? I hope so, or I hope he falls flat and Santorum can pick up the pieces.
No offense, but what you’re doing is a meaningless, static analysis. Santorum is able to draw votes away when Newt’s taken out of the poll because he has almost never been the target of negative ads in this campaign. When you compare Santorum and Newt on a level playing field, Newt runs away with it. Just compare where Newt was in early December before the Iowa attack ads started. He was ready to run away with the election. We don’t know how Santorum would fare under a negative ad assault, but there is EVERY reason to believe he would lose a lot of support under that assault. So the fact that a clean Santorum only performs a little better in the polls you selected against a bloodied and battered Newt shows that Newt has a lot more intrinsic strength.
As I said, you can’t instantly remove Santorum and expect Newt to start running away with the election. Newt needs to have a good campaign and good ads, and he doesn’t seem to have accomplished that yet. A two-man race between Mitt and anybody else would leave the opponent the target of negative ads and at a big disadvantage. Newt has shown at least off-and-on resilience in weathering that storm. We don’t know how Santorum would fare, but he did lose big in his last big election, and there is every reason to believe he would drop in the polls the same way Newt did under the barrage in Iowa and Florida.
So, bottom line, your analysis fails to factor in that in a two-man race between Santorum and Mitt, Santorum would be exposed to a big negative ad campaign that he has not yet been subject to in this race. That would surely worsen his standing in the polls and my estimation is he would be less able to withstand that barrage than Newt. Newt had truly GREAT moments in South Carolina that few other candidates have come close to in recent memory, so he has some powerful strengths that have given him resilience under some of Mitt’s attacks.