Republican presidential candidate former U.S. Senator <a gi-track='captionPersonalityLinkClicked' href=/galleries/search?phrase=Rick+Santorum&family=editorial&specificpeople=212911 ng-click='$event.stopPropagation()'>Rick Santorum</a> (R-PA) fields a question during 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.