Republican presidential hopefuls, from left, South Carolina Sen. Lindsay Graham, former New York Gov. George Pataki, Sen. Rick Santorum, Kentucky Sen. Rand Paul, former Arkansas Gov. Mike Huckabee, Florida Sen. Marco Rubio, Texas Sen. Ted Cruz, retired neurosurgeon Ben Carson, real estate magnate Donald Trump, former Florida Gov. Jeb Bush, Wisconsin Gov. Scott Walker, former CEO Carly Fiorina, Ohio Gov. John Kasich, and New Jersey Gov. Chris Christie, arrive on stage for the Republican presidential debate at the Ronald Reagan Presidential Library in Simi Valley, California, on Sept. 16, 2015.
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