2016 Republican presidential candidates Ben Carson, retired neurosurgeon, from left, Senator Marco Rubio, a Republican from Florida, Donald Trump, president and chief executive of Trump Organization Inc., Senator Ted Cruz, a Republican from Texas, and John Kasich, governor of Ohio, participate in the Republican presidential primary candidate debate sponsored by CNN and Telemundo at the University of Houston in Houston, Texas, U.S., on Thursday, Feb. 25, 2016. Donald Trump holds a substantial lead in the southern region where Republican voters have their say on March 1, displaying remarkable strength for a twice-divorced New Yorker in Bible Belt states home to some of the nation's most conservative voters. Photographer: Gary Coronado/Pool via Bloomberg