Newt Gingrich said Sunday that rival Mitt Romney's campaign would be "very badly weakened" by a loss in the Feb. 28 Michigan primary and dismissed the idea - floated by some conservatives concerned about the GOP field's performance - that an outside candidate could shake up the race.
"If he can't carry his home state, I think the rationale for why there is a Romney candidacy - he's not a candidate of ideas, he's not a candidate of ideology, he was the candidate because he was the inevitable winner," Gingrich said on Fox News Sunday. "There's a whole rationale which is now built on his ability to win, and he hasn't been able to win, and if he loses his home state… I don't see what he says the next morning to his donors to stay in the race."
"If any of the three of us lose our home state… I think you have a very, very badly weakened candidacy," Gingrich said.
"Given the chaos of this race, I don't want to say anything. But I am willing to say I think it is extraordinarily important to win your home state, and it has all sorts of underlying impact if you don't," he added.
Asked by host Chris Wallace about suggestions that a candidate like former Florida Gov. Jeb Bush should enter the Republican race to buoy conservative interest and morale, Gingrich said he had "no problem with anyone who wants to run," but cautioned that there were logistical and practical hurdles for a late entry.
"Anyone who feels they can come out and qualify, come play," Gingrich said.
But the former speaker warned that ballots would be tough to qualify for - and delegates difficult to collect - at this point. Gingrich also noted the temporary nature of other candidate's surges as they entered the race.
"Nobody's going to show up and become Superman or Superwoman so they just have to understand they're entering the arena," Gingrich said.
As for his struggling campaign, Gingrich said that he hoped to regain momentum through a positive campaign about "ideas," saying that's what fueled his previous surges.
"I've twice been the frontrunner… we're going to keep moving forward and gathering delegates," Gingrich said.
Of Rick Santorum, Gingrich admitted to having prematurely called for his exit from the race, but argued that he was still the superior choice among the "conservative wing" of the field.
"The biggest difference between me and Santorum is the scale of the idea, the boldness of the ideas, I'm much more willing to talk about fundamental change," Gingrich said.
Gingrich also defended the reported donation of an additional $10 million by billionaire casino mogul Sheldon Adelson to the super-PAC supporting his campaign. Adelson has already donated $11 million to Gingrich's efforts, and is by far his most generous supporter.
"He's certainly helping balance off Romney's 16 billionaires, and he's helping balance off Romney's Wall Street money."
Gingrich maintained that he and Adelson already shared views on Middle Eastern foreign policy, creating no conflict of interest.
"It's an open relationship. I'm very happy to say I think we should be worried about the Iranian nuclear weapon, I think we should do everything we can to make sure Israel survives," Gingrich said.