GOP presidential candidates Dr. Ben Carson, Donald Trump, Sen. Ted Cruz and Jeb Bush on stage during the CNN Republican presidential debate at the Venetian in Las Vegas on Dec. 15, 2015.
GOP presidential candidates Dr. Ben Carson, Donald Trump, Sen. Ted Cruz and Jeb Bush on stage during the CNN Republican presidential debate at the Venetian in Las Vegas on Dec. 15, 2015. Riccardo Savi Sipa/Tribune News Service
GOP presidential candidates Dr. Ben Carson, Donald Trump, Sen. Ted Cruz and Jeb Bush on stage during the CNN Republican presidential debate at the Venetian in Las Vegas on Dec. 15, 2015. Riccardo Savi Sipa/Tribune News Service