Republican presidential candidates, from left, former Pennsylvania Sen. Rick Santorum, former New York Gov. George Pataki, Sen. Rand Paul, R-Ky., former Arkansas Gov. Mike Huckabee, Sen. Marco Rubio, R-Fla., Sen. Ted Cruz, R-Texas, retired neurosurgeon Ben Carson, businessman Donald Trump, former Florida Gov. Jeb Bush, Wisconsin Gov. Scott Walker, businesswoman Carly Fiorina, Ohio Gov. John Kasich, and New Jersey Gov. Chris Christie take the stage during the CNN Republican presidential debate at the Ronald Reagan Presidential Library and Museum on Wednesday, Sept. 16, 2015, in Simi Valley, Calif. (AP Photo/Chris Carlson) | Chris Carlson
