Ben Carson, retired neurosurgeon and 2016 Republican presidential candidate, speaks during 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, president and chief executive of Trump Organization Inc. and 2016 Republican presidential candidate, 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