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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Minnesota Rep. Michele Bachmann, joined by husband Marcus (left) and family and friends, announces that she will end her campaign for president in West Des Moines on Wednesday. Chris Carlson/AP hide caption

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Texas Gov. Rick Perry speaks at a campaign event at Clark Electric Co-op on Dec. 27 in Osceola, Iowa. Perry's stance on immigration has troubled some Iowa voters. Justin Sullivan/Getty Images hide caption

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In a last bout of campaigning before Christmas, Rep. Michele Bachmann of Minnesota signs autographs at the National Motorcycle Museum in Anamosa, Iowa, on Dec. 22. Charlie Riedel/AP hide caption

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Republican presidential candidate former House Speaker Newt Gingrich speaks during a Republican presidential debate in Sioux City, Iowa, Thursday, Dec. 15, 2011. Eric Gay/AP hide caption

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Republican presidential candidates jockeyed for airtime when they met for their first prime time TV debate on Saturday night in South Carolina. Alex Wong/Getty Images hide caption

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Herman Cain (right) speaks as Texas Gov. Rick Perry looks on during a GOP presidential debate at Dartmouth College on Oct. 11.

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Republican presidential candidate Herman Cain speaks before Florida's straw poll at the Orange County Convention Center in Orlando on Saturday. Cain won the straw poll with 37 percent of the vote. Mark Wilson/Getty Images hide caption

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Republican presidential candidate former Massachusetts Gov. Mitt Romney, right, makes a point as Texas Gov. Rick Perry listens, during a debate in Orlando, Fla. Phelan M. Ebenhack/AP hide caption

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