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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Comedian Stephen Colbert, left, holds a rally with former GOP presidential candidate Herman Cain at the College of Charleston in South Carolina. Richard Ellis/Getty Images hide caption

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Alexandra Ziegler, age 9, leafletting for Gingrich in Greenville, S.C. Melissa Block/NPR hide caption

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Todd Palin attends the Iowa State Fair August 12, 2011 in Des Moines, Iowa. Chip Somodevilla/Getty Images hide caption

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Rep. Michele Bachmann, R-Minn., announces an end to her campaign for president on Wednesday in Des Moines, Iowa. Chris Carlson/AP hide caption

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A volunteer works the phones Tuesday at Newt Gingrich's New Hampshire campaign headquarters in Manchester. Alex Wong/Getty Images hide caption

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