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If Donald Trump convincingly beats Ted Cruz in Iowa, then all that stands between him and becoming the Republican presidential nominee is the endorsement of a single current GOP establishment figure, Charles Krauthammer said on "Special Report" tonight.

Krauthammer explained that Trump has gotten big endorsements from Bob Dole - who represents the GOP of yesteryear - and Sarah Palin - who doesn't fit the bill - but he hasn't gotten the support of a sitting Republican governor or senator.

"If you get somebody today from the so-called 'establishment' who endorses him, I think it becomes a flood," Krauthammer said. "[At] that point, the dam breaks, and you will get a rush of other establishment figures who will rally around him."

"And that could be the point at which he becomes inevitable as the nominee."

Why hasn't a sitting establishment figure endorsed Ted Cruz? Bret Baier asked.

"Well, I think the short answer is, everybody who knows him in the Senate hates him," Krauthammer said.

He explained that Cruz has gained the enmity of his fellow members of Congress by declaring they are "traitors" and part of the "Washington cartel," and he wears that enmity on his shirtsleeve with pride.

"Then, you get antipathy, and they will put that antipathy, perhaps, even over what's best for the party."

Watch more from the "Special Report" panel above.

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