Newt Gingrich speaks at Marquette University in Milwaukee on March 29. Rick Wood/MCT/Landov hide caption

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Newt Gingrich waves to supporters as he leaves a campaign stop in Buffalo, N.Y., last week. David Duprey/AP hide caption

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Former House Speaker Newt Gingrich, who wants to the the 2012 Republican presidential nominee, during a campaign event in Camp Hill, Pa., on Saturday (March 24, 2012). Jessica Kourkounis/Getty Images hide caption

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Former House Speaker Newt Gingrich. Win McNamee/Getty Images hide caption

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After his losses in Alabama and Mississippi on Tuesday, Newt Gingrich will face increasing pressure to drop out of the GOP race. Here he waves to supporters after speaking at a rally in Hoover, Ala., on Tuesday. Marvin Gentry /Reuters /Landov hide caption

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Republican candidate Newt Gingrich is counting on his promise of $2.50-per-gallon gas to return him to front-runner status. Evan Vucci/AP hide caption

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