The Note: What You Need To Know About Last Night’s Debate

— -- NOTABLES

--ANALYSIS -- DEBATE SHOWED WHAT TRUMP HAS ALREADY WON: Donald Trump may yet lose the Republican presidential nomination, and Thursday night’s debate offered hints of the fights that could make that possible, ABC’s RICK KLEIN writes. But the first GOP debate of 2016 revealed the extent to which Trump has already won. The slow-starting evening focused, for a change, on candidates not named Trump. It seemed to involve fewer than even the smallest-of-the-cycle debate field of seven. Yet when the candidates engaged with each other, they did so on terms Trump set. His chief rival in Iowa forced to respond to spurious doubts Trump has raised about whether Ted Cruz is even eligible to be president. http://abcn.ws/1JNIkSa

--BEST LINES OF THE REPUBLICAN DEBATE -- ABC’s PAOLA CHAVEZ highlights the best lines of the forum. http://abcn.ws/1J5ZZo3 WATCH THE DEBATE IN A MINUTE, courtesy of ABC’s TOM THORNTON and ALI DUKAKIS: http://abcn.ws/1JOnFgS

--5 MOMENTS THAT MATTERED AT THE 6TH GOP UNDERCARD DEBATE. Carly Fiorina, Mike Huckabee and Rick Santorum made their pitches to voters in the undercard debate Thursday night. ABC’s JENNIFER HANSLER, PAOLA CHAVEZ, and VERONICA STRACQUALURSI break down the five moments that mattered.  http://abcn.ws/1USTk17

--HOW RAND PAUL SPENT THE NIGHT OF THE DEBATE HE BOYCOTTED, courtesy of ABC’s ALANA ABRAMSON: http://abcn.ws/1SRhXgb

THIS WEEK ON “THIS WEEK”: Fresh off the first GOP debate of 2016, Republican presidential candidate Donald Trump sits down with George Stephanopoulos on the trail in New Hampshire, Sunday on "This Week." Then, with just 2 weeks remaining until the first-in-the-nation Iowa caucuses, Sen. Bernie Sanders comes to “This Week.” And, the powerhouse roundtable debates the week in politics with Republican strategist Kevin Madden, Washington Post columnist EJ Dionne, Republican strategist and CNBC contributor Sara Fagen, Democratic member of Congress and Progressive Caucus Co-Chair Rep. Keith Ellison, and ABC News Chief White House correspondent Jonathan Karl.

TODAY ON THE TRAIL with ABC’s SHUSHANNAH WALSHE:  Today Donald Trump is in Iowa where he holds a mid-morning rally. Chris Christie is also in Iowa, holding an evening fundraiser in Des Moines. Ted Cruz remains in South Carolina, as does Ben Carson and Mike Huckabee. This afternoon he holds a town hall in Columbia and tonight he holds a rally in North Greenville. Carson has a morning event in Charleston and Huckabee is there this afternoon for the Bully Pulpit Series followed by a tour of the Port of Charleston in nearby Mt. Pleasant. Marco Rubio, Jeb Bush, Carly Fiorina, John Kasich, and Rand Paul are all in New Hampshire. This morning Rubio holds a rally in Derry followed by a town hall in Henniker, a stop in Newport and another town hall in Claremont

YESTERDAY ON THE TRAIL with ABC’s JENNIFER HANSLER and VERONICA STRACQUALURSI

HOW TED CRUZ RESPONDED TO CITIZENSHIP AND GOLDMAN SACHS LOAN. From the GOP debate stage, presidential candidate Ted Cruz tackled the two big questions looming above his campaign: his citizenship and his failure to disclose two loans from big banks in a Federal Election Commission (FEC) filing. The New York Times reported this week that Cruz had failed to disclose nearly a million dollars in loans from Goldman Sachs and Citibank in his FEC Senate filing. Cruz seemed prepared and confident as he addressed the questions. "Thank you for passing on that hit piece on the front page of The New York Times," Cruz told the debate's moderators. Cruz has called it an "inadvertent" mistake and said his campaign has reached out to the FEC to amend the filing if needed, ABC’s JESSICA HOPPER reports. http://abcn.ws/1lci5t6

NOTED: CRUZ GOES AFTER DONALD TRUMP’S MOM IN BIRTHER BATTLE AT GOP DEBATE. In a heated back-and-forth at Thursday’s GOP debate, Sen. Ted Cruz directly responded to Donald Trump’s questioning of his eligibility to be president because he was born in Canada. “At the end of the day, the legal issue is quite straightforward,” Cruz said tonight. “I would note that the birther theories that Donald has been relying on, some of the more extreme ones insist that you must not only be born on U.S. soil but have two parents born on U.S. soil.” Cruz has said he is a U.S. citizen because his mother was an American citizen at the time of his birth. Cruz said if he were to be disqualified as president, so would Trump, ABC’s JENNIFER HANSLER and VERONICA STRACQUALURSI note. “Donald’s mother was born in Scotland. She was naturalized,” Cruz exclaimed. “But I was born here,” Trump fired back. http://abcn.ws/1RJ6QXO

CLINTON CAMPAIGN ACCUSES BERNIE SANDERS OF BREAKING PLEDGE NOT TO GO ‘NEGATIVE.’ The feud between the Hillary Clinton and Bernie Sanders campaigns is escalating. One day after Clinton went after Sanders for his healthcare plan, her campaign on Thursday accused the Vermont senator of going “negative” in a new ad that appears to draw a contrast between the two Democratic presidential candidates on their views about Wall Street. “We were very surprised today to see that Bernie Sanders had launched a negative television advertisement against Hillary,” Clinton campaign manager Robby Mook said yesterday afternoon on a conference call with reporters. According to ABC’s LIZ KREUTZ, Sanders, however, denies the ad -- which does not mention Clinton by name -- is about her.  http://abcn.ws/1OS6ECU

5 REASONS WHY THE RACE BETWEEN HILLARY CLINTON AND BERNIE SANDERS IS TIGHTENING. The race for the Democratic Party’s nomination is tighter than ever. Back-to-back polls appear to show Bernie Sanders with the momentum, gaining ground and even passing Secretary Clinton among likely caucus-goers in Iowa. Sanders appears to be sneaking up on Clinton nationally too. A new NYT/CBS poll this week showed Clinton with her smallest lead nationwide (Clinton 48 percent, Sanders 41). So where is Sanders’ support coming from? ABC’s CORINNE CATHCART, RYAN STRUYK and MARYALICE PARKS has more. http://abcn.ws/1Pe82vd

BUSH SLAMS TRUMP IN NEW AD FOR MOCKING DISABLED REPORTER. The political ad wars are in full effect. In advance of last night’s Republican debate, and less than a month before primary and caucus voting begins, Jeb Bush’s campaign has released a new ad attacking rival Republican Donald Trump for apparently mocking a disabled reporter, ABC’s CANDACE SMITH reports. The ad, titled “Enough,” is now airing in New Hampshire and is part of the campaign’s rotating $4.6 million ad buy in the state. http://abcn.ws/1OkGQOa

IN CASE YOU MISSED IT

THE NEW DONALD TRUMP ANTHEM YOU HAVE TO HEAR. Republican presidential candidate Donald Trump has a new campaign anthem, thanks to the musical group USA Freedom Kids, ABC’s PAOLA CHAVEZ explains. During a campaign stop in Pensacola, Florida, three of the group's five female members performed for the GOP front-runner at a Wednesday night rally. http://abcn.ws/1Ou25eb

WHO’S TWEETING?

@AshleyRParker: BIG SC NEWS: @LindseyGrahamSC to endorse Je Bush in SC today. http://www.nytimes.com/politics/first-draft/2016/01/15/lindsey-graham-to-endorse-jeb-bush-for-president/ …

@pivit: The winner of the #GOPDebate according to the @CNNPolitics Prediction Market is @tedcruz. His odds increased from 28% to 30% tonight.

@ZekeJMiller: Trump camp says ad backed by $1.1 million in IA and nearly $1m in NH http://www.donaldjtrump.com/media/our-country-tv-spot …

@amyewalter: This Carson $ story makes clear the Dr. (and donors) getting fleeced by his staff. http://www.politico.com/story/2016/01/ben-carsons-finance-chief-at-the-center-of-campaign-storm-217575 …

@nationaljournal: GOP opens new front in bid to stop Trump http://njour.nl/s/286095