The Note: What We Learned From Fight Night in Vegas

— -- NOTABLES

--IN CASE YOU MISSED IT -- THE GOP PRESIDENTIAL DEBATE IN A MINUTE, courtesy of ABC's ALI DUKAKIS and TOM THORNTON: http://abcn.ws/1RnJBBy

--ANALYSIS -- NEW FIGHTS EMERGE AS LEADING CANDIDATES TRY IGNORING DONALD TRUMP. Confronted with the durable phenomenon known as Donald Trump, the leading Republican presidential candidates tried a new tack Wednesday night: ignore him. Trump didn't go anywhere, of course. Attacks did flow in from candidates who found themselves farther from center stage than ever --- including, notably, Jeb Bush. But it's as if his front-running status is so familiar that his rivals for the most part chose not to fight him, as the race settles into its lanes, ABC's RICK KLEIN writes. The most tense exchanges pitted Ted Cruz against Marco Rubio, the onetime allies who now see themselves as each other's most serious rival. http://abcn.ws/1MgeeBe And ABC's SHUSHANNAH WALSHE takes us through the debate highlights on World News Now http://abcn.ws/1k2ggy8, as well as a look at where the state of the race is after that final GOP debate: http://abcn.ws/1QpExNh

--THE DEBATE'S BEST ONE-LINERS: The final debate of 2015, which focused on national security and terrorism, wasn't short of one-liners. ABC's PAOLA CHAVEZ rounded them up: http://abcn.ws/1Mg6gIi

TODAY ON THE TRAIL with ABC's SHUSHANNAH WALSHE: Donald Trump has a rally in Mesa, Arizona and tonight he appears on ABC's "Jimmy Kimmel Live.” Ted Cruz is in Los Angeles this morning where he will hold a news conference. Marco Rubio holds event in Ankeny, Iowa and Manchester, New Hampshire, hitting the first two early states in one day. Ben Carson remains in Nevada today. This afternoon he attends the Republican Women of Las Vegas Luncheon in Sin City followed by a rally in Carson City. Tonight he holds a rally in Elko. Carly Fiorina and Rand Paul are also in Nevada. John Kasich stops in Utah this afternoon touring Salt Lake City Welfare Square before heading to Iowa for an evening town hall. Jeb Bush is off the trail fundraising in Nevada and California. Chris Christie is also raising money in California, stopping in the donor rich enclaves of Palo Alto and Beverly Hills. Meanwhile, Hillary Clinton is in Nebraska and Iowa. This afternoon, she will appear with Warren Buffet in Omaha to discuss her economic agenda. Bernie Sanders is in Washington, DC where he will visit a mosque--like Martin O'Malley did last week-- for an interfaith roundtable.

THE BUZZ

with ABC's VERONICA STRACQUALURSI and PAOLA CHAVEZ

DONALD TRUMP 'OPEN' TO 'CLOSING' PARTS OF THE INTERNET TO FIGHT ISIS. Donald Trump acknowledged last night that he would be open to "closing" down parts of the Internet in order to squelch the recruitment efforts of the Islamic State. CNN's Wolf Blitzer, one of the moderators, asked Trump if he would be open to closing parts of the Internet even if that put the U.S. in the company of China and North Korea, which censor parts of the web, ABC's VERONICA STRACQUALURSI reports. "I would certainly be open to closing areas where we are at war with somebody," Trump said. "I sure as hell don't want to let people that want to kill us and kill our nation use our internet. Yes, sir. I am." http://abcn.ws/1JaLuK4

JEB BUSH ON TRUMP: HE'S A 'CHAOS CANDIDATE' AND HE'D BE A 'CHAOS PRESIDENT.' Trump, unsurprisingly, was asked about his proposal to ban all immigration by Muslims. "As far as other people, like in the migration where they're going, tens of thousands of people having cell phones with ISIS flags on them,” Trump said. He added, "And if I'm president and if Obama has brought some to this country, they are leaving. They're going. They're gone." Former Florida Gov. Jeb Bush was asked about earlier comments calling Trump "unhinged,” ABC's CANDACE SMITH notes. "Donald, you know, is great 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 declared. http://abcn.ws/1mmQkPH

FACT CHECK -- CHRIS CHRISTIE SAYS HE'LL BE MORE TRUSTED BY (DEAD) KING OF JORDAN. Chris Christie said that he'll be more trusted by the King Hussein of Jordan than President Obama in his strategy to defeat ISIS. Only problem is that Hussein has been dead since 1999. ABC's JORDYN PHELPS notes King Abdullah II is the current, living king of Jordan. http://abcn.ws/1mmV7Aw

THE MOMENTS THAT MATTERED AT THE 5TH REPUBLICAN UNDERCARD PRESIDENTIAL DEBATE. Four presidential candidates whose combined national polling numbers are in the low single digits, gathered on the "undercard” debate stage in Las Vegas last night with seemingly little hope of breaking into the top tier as the first nominating contests of 2016 approach. Each of the Republican contenders sought to convince voters, for the last time this year, that they deserve another look. ABC's JOHN VERHOVEK, MERIDITH MCGRAW, ALI DUKAKIS, PAOLA CHAVEZ and VERONICA STRACQUALURSI look at 7 moments that mattered at the final "undercard” debate of 2015. http://abcn.ws/1P60WM7

HILLARY CLINTON: 'GEORGE BUSH WAS RIGHT' ON ISLAMOPHOBIA. Hillary Clinton yesterday praised former Republican President George W. Bush for his position regarding Muslims following the 9/11 terrorist attacks. "I want to remind us, particularly our Republican friends, that George Bush was right," the Democratic presidential frontrunner said during remarks at the University of Minnesota in Minneapolis. "Six days after 9/11, he went to a Muslim community center and here's what he said: 'Those who feel like they can intimidate our fellow citizens to take out their anger don't represent the best of America, they represent the worst of humankind and they should be ashamed of that kind of behavior.'” ABC's LIZ KREUTZ reports Clinton made the remark after assailing the current Republican field for inciting anti-Muslim rhetoric in the wake of the ISIS-inspired shooting in San Bernardino, California. http://abcn.ws/1I7v2zB

IN CASE YOU MISSED IT

THE COUGH THAT CONSUMED THE GOP DEBATE. Amid the rhetorical brawls and ISIS policy plans, there was something else that pervaded the GOP debate Tuesday: The cough. At the beginning of the GOP debate Tuesday night, someone let out a cough. And the Internet went wild over who it could have been. ABC's ALANA ABRAMSON notes even celebrities watching were curious. http://abcn.ws/1TOWRgB

WHO'S TWEETING?

@amyewalter: If you were looking for this 5th GOP debate to shake-up the GOP race, you were sorely disappointed. http://cookpolitical.com/story/9097

‏@TheFix: Did a debate moderator just get Donald Trump to back down? Yes. Yes he did. http://wpo.st/5UWx0

@SalenaZitoTrib: The time @realDonaldTrump pinky square promised @hughhewitt he would not mount 3rd party run https://shar.es/1G5j2X

@HotlineJosh: Debate exposed the central GOP divide on foreign policy: hawkish party of Bush/Rubio or restrained vision of Cruz http://www.nationaljournal.com/s/126117?mref=home_top_side_2 ...

@nickconfessore: The basic Trump-Cruz calculation is that if they lay off each other, they can starve the other guys out and make it to April. It's possible.