Republican presidential candidates Donald Trump (right) and Wisconsin Gov. Scott Walker speak together during a commercial break at the first Republican presidential debate in Cleveland on Thursday. Trump's remarks about Fox News debate moderator Megyn Kelly have triggered a firestorm. Andrew Harnik/AP hide caption

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Newt Gingrich greets supporters during a rally at Wings Plus in Coral Springs, Fla., on Jan. 25. The GOP candidates meet in Jacksonville Thursday night for a final debate before Tuesday's primary. Carline Jean/MCT/Landov hide caption

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Former Massachusetts Gov. Mitt Romney (left) and Texas Gov. Rick Perry got into a heated exchange about immigration during Tuesday's GOP presidential debate in Las Vegas.

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Former Massachusetts Gov. Mitt Romney maintained his frontrunner status in the GOP presidential debate at Dartmouth College on Tuesday.

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