Barb Hansen tallies votes during a GOP caucus in precinct 42 near Smithland, Iowa, on Tuesday, Jan. 3, 2012. Dave Weaver/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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Gingrich with one of the many pieces of farm equipment he encountered on a last-minute campaign swing through Iowa. This tractor was on display at the Heartland Acres Agribition Center on Monday in Independence, Iowa. Andrew Burton/Getty Images hide caption

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A supporter of Texas governor Rick Perry places campaign signs outside the Hotel Pattee before an event on Monday in Perry, Iowa. Andrew Burton/Getty Images hide caption

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Edward Lewis of Council Bluffs waved an Iowa state flag outside the Family Table Restaurant in Atlantic on Sunday, before the arrival of former Massachusetts governor and Republican presidential candidate Mitt Romney. Chip Somodevilla/Getty Images hide caption

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Former Massachusetts Gov. Mitt Romney greets voters after speaking at the Mississippi Valley Fairgrounds on Wednesday in Davenport, Iowa. Win McNamee/Getty Images hide caption

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Fired up on a cold day: Sunday in Ames, Iowa, Marilyn Izette Krocheski came to the West Towne Pub to see Republican presidential candidate Newt Gingrich. Andrew Burton/Getty Images hide caption

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Former Massachusetts Gov. Mitt Romney campaigns Sunday in Council Bluffs, Iowa. Justin Sullivan/Getty Images hide caption

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Newt Gingrich attends Catholic Mass at St. Ambrose Cathedral on Sunday in Des Moines, Iowa, with his wife, Callista, right. Evan Vucci/Associated Press hide caption

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