Republican presidential candidate Mitt Romney pauses during a visit to St. Paul's Lutheran Church while campaigning in Berlin, N.H., on Dec. 22. Charles Krupa/AP hide caption

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President Obama greets students after speaking at the University of Michigan in Ann Arbor on Jan 27. Young Republicans say they see an opportunity in 2012 to dent Obama's popularity among the youngest voters. Jewel Samad/AFP/Getty Images hide caption

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Former Pennsylvania Sen. Rick Santorum speaks at the Bella Donna Chapel in McKinney, Texas, on Wednesday. Rex C. Curry/Associated Press hide caption

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A Mitt Romney supporter holds up a sign showing her love for Romney and Denver Broncos quarterback Tim Tebow at a rally for the GOP presidential candidate at Arapahoe High School this week in Centennial, Colo. Marc Piscotty/Getty Images hide caption

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Men arrive at a campaign rally for Mitt Romney in Elko, Nev., on Friday. Emmanuel Dunand/AFP/Getty Images hide caption

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Brett O'Donnell, right, at the Republican National Convention in St. Paul, Minn., Sept. 4, 2008. O'Donnell worked with GOP presidential candidate John McCain as his debate coach. Charles Dharapak/ASSOCIATED PRESS hide caption

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Mitt Romney, accompanied by Rep. Ileana Ros-Lehtinen, R-Fla. (third from right), campaigns Wednesday at a U.S.-Cuba Democracy Political Action Committee event at Miami-Dade College in Miami. Charles Dharapak/AP hide caption

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President Obama tours Conveyor Engineering and Manufacturing in Cedar Rapids, Iowa, on Wednesday. Jewel Samad/AFP/Getty Images hide caption

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Newt Gingrich is refuting new attacks about his role at mortgage giant Freddie Mac. Gingrich's reflection is seen here as he walks out mirrored doors in Tampa, Fla. to deliver remarks and greet supporters on Jan. 23. PAUL J. RICHARDS/AFP/Getty Images hide caption

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