Former Massachusetts Gov. Mitt Romney waves to the crowd as he is introduced at the start of Wednesday night's Republican presidential debate in Mesa, Ariz. Ross D. Franklin/AP hide caption

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Republican presidential hopeful and former U.S. Sen. Rick Santorum speaks to supporters, flanked by his daughter, Elizabeth (left), and wife, Karen. Whitney Curtis/Getty Images hide caption

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Jan White, left, Brenda Robertson, center, and Janet Freixas, right, count paper ballots at the headquarters of the Douglas County Republican Party Saturday in Minden, Nev., following county-wide Nevada caucus meetings. Ted S. Warren/AP hide caption

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Mitt Romney at his state campaign headquarters Tuesday in Tampa, Fla. Joe Raedle/Getty Images hide caption

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On Thursday night in Jacksonville, Fla., Mitt Romney (right) went after Newt Gingrich from the start on topics such as immigration and colonizing the moon. Matt Rourke/AP hide caption

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Iowa caucusgoers deposit their ballots on Jan. 3 at a school in Des Moines. On Thursday, the state GOP said it could not account for all votes from the caucuses. Jewel Samad /Getty Images hide caption

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Former Utah Gov. Jon Huntsman was surrounded by members of the media during a campaign stop earlier this month in Dover, N.H. Alex Wong/Getty Images hide caption

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Republican presidential candidate former U.S. Sen. Rick Santorum speaks to supporters after announcing that he was endorsed Saturday by the evangelical Christian leaders group. Mark Wilson/Getty Images hide caption

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