GOP Debate Score Card: How Did the Candidates Fare?

LAS VEGAS -- In a battle of the polling heavyweights, Donald Trump found himself the center of attention at the final GOP debate of 2015. Sens. Ted Cruz, R-Texas, and Marco Rubio, R-Fla., also sparred in what could be a preview of things to come.

This debate was not without some news. And leave it to Trump to deliver it.

"Are you ready to reassure Republicans tonight that you will run as a Republican and abide by the decision of the Republicans?" probed moderator Hugh Hewitt.

"I really am. I'll be honest, I really am. I mean, people have been putting me in a crunch. I really am….I am totally committed to the Republican Party. I feel very honored to be the frontrunner," Trump said.

Trump and Cruz came into this debate in the number one and two slots, but it was former Florida Gov. Jeb Bush, not Cruz, who wanted to tangle with Trump.

It started at the outset when Trump defended his strict policies on immigration and temporarily banning Muslims from America.

"We are not talking about isolation. We're talking about security. We're not talking about religion. We're talking about security," Trump explained.

Cruz tried to show how his approach differed from Trump's Muslim statement without insulting him.

"I understand why Donald made that proposal. I introduced legislation in the Senate that I believe is more narrowly focused at the actual threat, which is radical Islamic terrorism. And what my legislation would do is suspend all refugees for three years from countries where ISIS or al Qaeda control substantial territory," Cruz explained.

"It's not a war on a faith; it's a war on a political and theocratic ideology that seeks to murder us," Cruz said.

Bush: Trump's a 'Chaos Candidate'

But while Cruz went easy on Trump, Bush did not.

"If we're going to ban all Muslims, how are we going to get them to be part of a coalition to destroy ISIS?" Bush probed.

"So Donald, you know, is great at -- at the one-liners, but he's a chaos candidate. And he'd be a chaos president. He would not be the commander in chief we need to keep our country safe," Bush charged.

Bush also took issue when Trump made the following statement about taking out the family members of ISIS.

"I would be very, very firm with families. Frankly, that will make people think because they may not care much about their lives, but they do care, believe it or not, about their families' lives," Trump said, to the applause of the crowd.

"The idea that that is a solution to this is just -- is just crazy," Bush declared. "That is not a serious kind of candidate."

"Look, look, look. We need a toughness," Trump responded. "We need strength. We're not respected, you know, as a nation anymore."

"Donald, you're not going to be able to insult your way to the presidency. That's not going to happen," Bush replied.

"With Jeb's attitude, we will never be great again, that I can tell you. We will never be great again," Trump rebutted.

Cruz vs. Rubio

Beyond the squabbling, one of the big storylines was the differences between Cruz and Rubio.

Despite Trump's dominance, both campaigns see each other as their main rival. Consequently, disagreements centered on plenty of topics such as immigration.

"He was fighting to grant amnesty and to secure the border, and I was fighting to secure the border," Cruz noted.

Rubio replied, "Ted Cruz supported a 500 percent increase in the number of H-1B visas, the guest workers that are allowed into this country, and Ted supports doubling the number of green cards."

They also differed on whether to take out bad dictators around the world.

"Assad is a bad man. Gadhafi was a bad man. Mubarak had a terrible human rights record. But they were assisting us -- at least Gadhafi and Mubarak -- in fighting radical Islamic terrorists," Cruz stated.

"Anti-American dictators like Assad, who help Hezbollah, who helped get those IEDs into Iraq, if they go, I will not shed a tear," Rubio retorted.

Ben Carson's Sagging Poll Numbers

As for Ben Carson, the retired neurosurgeon has seen his poll numbers drop substantially over the last few weeks. Voters seem to question his foreign policy chops and nice guy demeanor in standing up against a vicious enemy like ISIS.

Carson explained how he would go after them.

"Tough, resolute, understanding what the problems are, and understanding that the job of the president of the United States is to protect the people of this country and to do what is necessary in order to get it done," Carson said.

This is the last debate for 2015. The candidates will reconvene in mid-January when the Republicans gather in Charleston, South Carolina.

Where do things stand right now? Trump is in the pole position, with Cruz nipping at his heels. Rubio remains a player and Carson is just hoping to survive. There are 45 days left until the Iowa caucus where voting begins Feb. 1.