LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates (L-R) George Pataki, Mike Huckabee, Rick Santorum and Sen. Lindsey Graham (R-SC) are introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate U.S. Sen. Lindsey Graham (R-SC) speaks during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Mike Huckabee (2nd L) speaks as George Pataki (L), Rick Santorum (2nd R) and U.S. Sen. Lindsey Graham (R-SC) listen during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Mike Huckabee waves as he is introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate George Pataki (L) speaks as Mike Huckabee listens during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates (L-R) Mike Huckabee, Rick Santorum and Sen. Lindsey Graham (R-SC) are introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate U.S. Sen. Lindsey Graham (R-SC) speaks as Rick Santorum listens during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Mike Huckabee speaks during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates Donald Trump (L) and Sen. Ted Cruz (R-TX) shake hands as they are introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates (L-R) Ohio Gov. John Kasich, Carly Fiorina, Sen. Marco Rubio (R-FL), Ben Carson, Donald Trump, Sen. Ted Cruz (R-TX), Jeb Bush, New Jersey Gov. Chris Christie and Sen. Rand Paul (R-KY) are introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates (L-R) Ohio Gov. John Kasich, Carly Fiorina, Sen. Marco Rubio (R-FL), Ben Carson, Donald Trump, Sen. Ted Cruz (R-TX), Jeb Bush, New Jersey Gov. Chris Christie and Sen. Rand Paul (R-KY) are introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Donald Trump is introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate New Jersey Gov. Chris Christie speaks during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate U.S. Sen. Rand Paul (R-KY) speaks during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Jeb Bush speaks during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate U.S. Sen. Marco Rubio (R-FL) waves as he walks onstage during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Carly Fiorina (R) speaks as CNN anchor Wolf Blitzer listens during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Ohio Gov. John Kasich speaks during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Ben Carson speaks during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates (L-R) Ben Carson, Donald Trump and Sen. Ted Cruz (R-TX) stand on stage as they are introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Sen. Ted Cruz (R-TX) waves as he is introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates Donald Trump (L) and Sen. Ted Cruz (R-TX) applaud as they are introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Jeb Bush waves as he is introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates Donald Trump (L) and Jeb Bush (R) repond to each other as U.S. Sen. Ted Cruz (R-TX) listens during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Donald Trump during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Donald Trump during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Donald Trump speaks during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate U.S. Sen. Ted Cruz (R-TX)speaks during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Carly Fiorina (R) speaks as CNN anchor Wolf Blitzer listens during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Donald Trump (C) gestures as Ben Carson (L) and U.S. Sen. Ted Cruz (R-TX) look on as during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate U.S. Sen. Ted Cruz (R-TX) (R) speaks as Donald Trump listens during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates Ben Carson (L) and Donald Trump participate in the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: (L-R) CNN anchor Wolf Blitzer looks on as Republican presidential candidates Ohio Gov. John Kasich, Carly Fiorina, Sen. Marco Rubio (R-FL), Ben Carson, Donald Trump, Sen. Ted Cruz (R-TX), Jeb Bush, New Jersey Gov. Chris Christie and Sen. Rand Paul (R-KY) are introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates Ben Carson and Donald Trump talk during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate New Jersey Gov. Chris Christie (C) speaks as Jeb Bush (L) and U.S. Sen. Rand Paul (R-KY) listen during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate U.S. Sen. Rand Paul (R-KY) (R) speaks as New Jersey Gov. Chris Christie listens during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Donald Trump speaks during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Donald Trump (L) pats U.S. Sen. Ted Cruz (R-TX) after a comment during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Donald Trump (C) speaks as Ben Carson (L) and U.S. Sen. Ted Cruz (R-TX) listen as during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Donald Trump talks to New Jersey Gov. Chris Christie during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Jeb Bush speaks during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Carly Fiorina is introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates Sen. Marco Rubio (R-FL) (L) and Ben Carson participate during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Ohio Gov. John Kasich waves as he is introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Ethan Miller/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Donald Trump smiles (C) as New Jersey Gov. Chris Christie (L), Jeb Bush (2ndL), Ohio Gov. John Kasich (2nd R) and U.S. Sen. Rand Paul (R-KY) walk onstage afterthe CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates Donald Trump and U.S. Sen. Ted Cruz (R-TX) talk during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidates Donald Trump (L) and Sen. Ted Cruz (R-TX), interact during the CNN republican presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates. (Photo by Justin Sullivan/Getty Images)
GOP Presidential Candidates Debate In Las Vegas
LAS VEGAS, NV - DECEMBER 15: Republican presidential candidate Donald Trump (C) speaks as Ben Carson (L) and U.S. Sen. Ted Cruz (R-TX) listen as during the CNN Republican presidential debate on December 15, 2015 in Las Vegas, Nevada. This is the last GOP debate of the year, with U.S. Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls. (Photo by Justin Sullivan/Getty Images)
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Republican presidential candidates (L-R) Ohio Gov. John Kasich, Carly Fiorina, Sen. Marco Rubio (R-FL), Ben Carson, Donald Trump, Sen. Ted Cruz (R-TX), Jeb Bush, New Jersey Gov. Chris Christie and Sen. Rand Paul (R-KY) are introduced during the CNN presidential debate at The Venetian Las Vegas on December 15, 2015 in Las Vegas, Nevada. Thirteen Republican presidential candidates are participating in the fifth set of Republican presidential debates.