5th Republican debate

Highlights of the last Republican debate of the year, with Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls, Dec. 15, 2015.

Republican presidential candidates Ohio Gov. John Kasich, Carly Fiorina, U.S. Sen. Marco Rubio (R-FL), Ben Carson, Donald Trump, U.S. Sen. Ted Cruz (R-TX), Jeb Bush, New Jersey Gov. Chris Christie and U.S. Sen. Rand Paul (R-KY) stand on stage during the CNN Republican presidential debate on Dec. 15, 2015 in Las Vegas.

Carson & Trump

Ben Carson, left, and Donald Trump laugh after Carson made a comment about starting to sound like Trump in Las Vegas.

Donald Trump & Ted Cruz

Donald Trump (L) speaks as Sen. Ted Cruz (R-TX) listens during the CNN Republican presidential debate on Dec.15, 2015 in Las Vegas.

Marco Rubio

Sen. Marco Rubio speaks during the Republican presidential debate in Las Vegas.

Rubio and Cruz debated forcefully about

Carly Fiorina

Carly Fiorina responds to a question from debate moderator Wolf Blitzer during the Republican presidential debate in Las Vegas, Dec. 15, 2015.

GOP debate

Donald Trump, second from left, makes a point as Ben Carson, left, Ted Cruz, second from right, and Jeb Bush look on.

Republican debate

Donald Trump and former Gov. Jeb Bush are seen debating on video monitors in the press room during the Republican presidential debate.

Ted Cruz

Sen. Ted Cruz (R-TX) speaks during the CNN Republican presidential debate in Las Vegas.

Republican debate

Republican presidential candidate Jeb Bush (R) speaks as Donald Trump (L) and Sen. Ted Cruz (R-TX) listen during the CNN Republican presidential debate in Las Vegas.

Bush told Trump he "can't insult his way to the presidency."

Ben Carson

Dr. Ben Carson speaks during the Republican presidential debate in Las Vegas.

Jeb Bush

Jeb Bush told Trump, "Donald you're not going to be able to insult your way to the presidency."

John Kasich

Ohio Gov. John Kasich speaks during the Republican debate in Las Vegas.

Rand Paul

Rand Paul criticized Trump's proposal to kill the families of terror suspects: "If you're going to support Donald Trump are you going to get rid of the Constitution?"

Chris Christie

New Jersey Gov. Chris called President Barack Obama a "feckless weakling."

Sen. Ted Cruz (R-TX) (R) speaks as Donald Trump listens in Las Vegas.

Republican debate

(L-R) Dr. Ben Carson, businessman Donald Trump and Sen. Ted Cruz hold their hands over their hearts for the singing of the U.S. national anthem before the start of the Republican presidential debate in Las Vegas.

Republican debate

Ayla Brown sings the U.S. national anthem as Republican presidential candidates (L-R) Gov. John Kasich, former HP CEO Carly Fiorina, Sen. Marco Rubio, Dr. Ben Carson, businessman Donald Trump, Sen. Ted Cruz, former Gov. Jeb Bush, Gov. Chris Christie and Sen. Rand Paul listen before the Republican presidential debate in Las Vegas.

Republican debate

(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 in Las Vegas.

Ted Cruz

Sen. Ted Cruz waves as he arrives on stage for the fifth Republican debate in Las Vegas.

Rick Santorum & Lindsey Graham

Sen. Lindsey Graham (R-SC) speaks as former Sen. Rick Santorum turns away during the so-called undercard debate on Dec. 15, 2015 in Las Vegas.

Republican debate

Former Gov. George Pataki speaks as former Gov. Mike Huckabee looks on during the Republican presidential debate in Las Vegas.

Pataki told the audience "Donald Trump is the know-nothing candidate of the 21st century and cannot be our nominee."

Mike Huckabee

Former Gov. Mike Huckabee speaks in a forum for lower polling candidates held prior to the main Republican presidential debate in Las Vegas.

In reference to the idea of monitoring mosques, Huckabee said, "No, it does not violate their First Amendment right to go and listen to their sermons."

Rick Santorum

Former Sen. Rick Santorum speaks during the Republican presidential debate in Las Vegas.

He told the audience, "Islam is fundamentally different," and Islam is not just a religion. It's also a political governing structure."

Lindsey Graham

Sen. Lindsey Graham delivers his opening statement during a forum for lower polling candidates held prior to the main Republican presidential debate in Las Vegas.

Graham said, "Leave Islam alone. Go after the radicals." he continued, "Bottom line is we're at war. They're coming to kill us all."

Graham declared, "I blame Obama for this mess. I miss George W. Bush. I wish he were president right now. We wouldn't be in this mess."

Republican debate

Former Gov. Mike Huckabee (L) and former Sen. Rick Santorum (C) listen as Sen. Lindsey Graham (R) speaks on stage.

Republican debate

Sen. Rick Santorum (2nd R) answers a question from debate moderator Wolf Blitzer (foreground) as (L-R) former Gov. George Pataki, former Gov. Mike Huckabee and Sen. Lindsey Graham (R) look on during the Republican presidential debate in Las Vegas.

George Pataki

Former New York Gov. George Pataki delivers his opening statement during a forum for lower polling candidates held prior to the Republican presidential debate in Las Vegas.

Pataki praised the former New York Police Department program of monitoring mosques.

George Pataki & Mike Huckabee

Former Gov. George Pataki (L) and former Gov. Mike Huckabee (C) talk with debate moderator and Salem Radio Network talk show host Hugh Hewitt (R) during a commercial break during the Republican presidential debate in Las Vegas.

Lindsey Graham

Sen. Lindsey Graham has his tie straightened by a debate staff member during a commercial break in the midst of a forum for lower polling candidates held before the main Republican presidential debate in Las Vegas.

Republican debate

General view of the venue as CNN's Wolf Blitzer (L) moderates as former New York Gov. George Pataki, former Arkansas Gov. Mike Huckabee, former Pennsylvania Sen. Rick Santorum and South Carolina Sen. Lindsey Graham (L to R) participate in a forum for lower polling candidates held before the Republican presidential debate in Las Vegas, Nevada December 15, 2015.

Republican debate

(L-R) Former Gov. Mike Huckabee, former Sen. Rick Santorum and Sen. Lindsey Graham applaud on stage in Las Vegas.

Republican debate

Highlights of the last Republican debate of the year, with Sen. Ted Cruz (R-TX) gaining in the polls in Iowa and other early voting states and Donald Trump rising in national polls, Dec. 15, 2015.

Former New York Gov. George Pataki, former Arkansas Gov. Mike Huckabee, former Pennsylvania Sen. Rick Santorum and South Carolina Sen. Lindsey Graham (L to R) pose before participating in a forum for lower polling candidates held before the main Republican presidential debate in Las Vegas, Dec. 15, 2015.

Republican debate

Former Gov. George Pataki, former Gov. Mike Huckabee, former Sen. Rick Santorum and Sen. Lindsey Graham (R-SC) stand on stage before during the Republican presidential debate in Las Vegas.