DES MOINES, IA - JANUARY 28:  Republican presidential candidates Sen. Ted Cruz (R-TX) (R) shakes hands with Ben Carson (L) after the Fox News - Google GOP Debate January 28, 2016 at the Iowa Events Center in Des Moines, Iowa. Residents of Iowa will vote for the Republican nominee at the caucuses on February 1. Donald Trump, who is leading most polls in the state, decided not to participate in the debate.  (Photo by Scott Olson/Getty Images)