Republican presidential candidates former U.S. Senator Rick Santorum... News Photo2012 United States Presidential Election,Bestof,Democracy,Election,Former,Horizontal,Iowa,Jon M. Huntsman Jr.,Massachusetts,Michele Bachmann,Mitt Romney,Newt Gingrich,Politics,Presidential Candidate,Republican Party,Rick Perry - Politician,Rick Santorum,Ron Paul,Sioux City,Texas,Topics,Topix,US Republican Party Presidential Candidate,USAPhotographer Collection: Getty Images News 2011 Getty ImagesSIOUX CITY, IA - DECEMBER 15: Republican presidential candidates (L-R) former U.S. Senator Rick Santorum (R-PA), Texas Gov. Rick Perry, former Massachusetts Gov. Mitt Romney, former Speaker of the House Newt Gingrich, U.S. Rep. Ron Paul (R-TX), U.S. Rep. Michele Bachmann (R-MN), and former Utah Governor Jon Huntsman Jr. are introduced for the Fox News Channel debate at the Sioux City Convention Center on December 15, 2011 in Sioux City, Iowa. The GOP contenders are in the final stretch of campaigning in Iowa where the January 3rd caucus is the first test the candidates must face before becoming the Republican presidential nominee. (Photo by Scott Olson/Getty Images)