DES MOINES, IA - MAY 16:  Former Pennsylvania Senator Rick Santorum speaks to guests gathered for the Republican Party of Iowa's Lincoln Dinner at the Iowa Events Center on May 16, 2015 in Des Moines, Iowa. The event sponsored by the Republican Party of Iowa gave several Republican presidential hopefuls an opportunity to strengthen their support among Iowa Republicans ahead of the 2016 Iowa caucus.  (Photo by Scott Olson/Getty Images)