Former House Speaker Newt Gingrich, a one-time history professor, educates delegates gathering in Tampa, Fla., on how to get the party message out. The event was billed as "Newt U." Brakkton Booker/NPR 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

itoggle caption Jessica Kourkounis/Getty Images

Rick Santorum told voters in Mandeville, La. on Wednesday that they were "not looking for someone who's the Etch A Sketch candidate." Sean Gardner /Reuters /Landov hide caption

itoggle caption Sean Gardner /Reuters /Landov

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

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Jim Wilson of Buckingham, Va., who supports Republican presidential candidate Mitt Romney, walks past a bus during a Romney campaign stop Monday in Springfield, Ill. Steven Senne/AP hide caption

itoggle caption Steven Senne/AP