From left, former Pennsylvania Sen. Rick Santorum, former Massachusetts Gov. Mitt Romney, former House Speaker Newt Gingrich and Texas Rep. Ron Paul, at a debate Thursday in Charleston, S.C. Win McNamee/Getty Images hide caption

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Mitt Romney and Newt Gingrich face off at the ABC News GOP Presidential Debate on Dec. 10. Kevork Djansezian/Getty Images hide caption

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Republican presidential candidates Mitt Romney (left) and Newt Gingrich shake hands after a Republican presidential debate in Tampa, Fla. Mike Carlson/AP hide caption

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President Obama received a warm welcome at Scranton High School in Scranton, Pa., Wednesday. A surge in Hispanic voters in that state could make his chances of winning it a little more likely. Carolyn Kaster/AP hide caption

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Republican presidential candidate Mitt Romney speaks during a town hall event in Peterborough, N.H., on Saturday. Michael Dwyer/AP hide caption

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