The Note: Democrats Get Ready to Duel in New Hampshire

— -- NOTABLES

--SANDERS CAMP FIRES STAFFER FOR ACCESSING CLINTON CAMPAIGN DATA: A member of the Sanders campaign has been fired after wrongfully accessing modeling data from the Clinton campaign. According to the story first reported by the Washington Post, the DNC suspended the Sanders campaign's access to its party voter data after discovering the breach, a move that could seriously impact the Vermont senator's field organizing and campaigning efforts just weeks before the first primary votes are cast. Michael Briggs, spokesperson for the Sanders campaign, blamed the incident on the software vendor used by the DNC, ABC's MARYALICE PARKS reports. "Sadly, the vendor who runs the DNC's voter file program continues to make serious errors. On more than one occasion, the vendor has dropped the firewall between the data of different Democratic campaigns. Our campaign months ago alerted the DNC to the fact that campaign data was being made available to other campaigns," Briggs wrote in a statement to ABC News. http://abcn.ws/1QwIi38

--WHAT THE DNC IS SAYING: Statement from Luis Miranda, DNC spokesman: "The DNC was notified on Wednesday by its data systems vendor NGP VAN that as a result of a software patch, all users on the system across Democratic campaigns were inadvertently able to access some data belonging to other campaigns for a brief window. The DNC immediately directed NGP VAN to conduct a thorough analysis to identify any users who accessed the data, what actions they took in the system, and to report on the findings to the Party and any affected campaign. We have also instructed NGP VAN to conduct a full audit of the system to ensure the integrity of the data and the security of the system for the campaigns that use it, and to begin a review process with every campaign and user to ensure they understand and abide by the rules governing the use of the system."

--ANALYSIS -- ABC's RICK KLEIN: Could a data breach burn the Bern? The run-up to the next Democratic presidential debate was shaping up as a Bernie Sanders moment, with eye-popping contributor numbers and impressive new endorsements suggesting momentum his campaign needs in the stretch. But news that his campaign was engaged in a data breach involving Hillary Clinton's campaign suggests something between incompetence and nefarious motives. It will definitely be a distraction for a campaign powered in part by the candidate's purity, and could become worse than that if the campaign doesn't win back access to voter data files, and fast. The Democratic contest has been an uncommonly friendly affair to this point. But Sanders can't afford rough spots at this sensitive stage of the game.

--THIS WEEK ON "THIS WEEK": George Stephanopoulos anchors a special edition of "This Week" live from New Hampshire, with guests including presidential candidates Governor Chris Christie, Senator Bernie Sanders, and Donald Trump. And, the powerhouse roundtable debates the week in politics with Democratic strategist and ABC News contributor Donna Brazile, ABC News political analyst Matthew Dowd, ABC News contributor Ana Navarro, and ABC News' Cokie Roberts. See the whole political picture Sunday on "This Week."

PRE-DEBATE SPEED READ

HILLARY CLINTON TAKES BIG LEAD INTO DEBATE BUT WITH A TRUSTWORTHINESS DEFICIT. Hillary Clinton maintains a commanding lead for the Democratic presidential nomination heading into tomorrow's ABC News debate -- but with notable weakness on honesty and trustworthiness, a challenge not just in the primaries but in a potential general election contest ahead. Clinton leads Bernie Sanders by 31 percentage points, 59-28 percent, among Democrats and Democratic-leaning independents who are registered to vote in the latest ABC News/Washington Post poll, with Martin O'Malley in the single digits. And Clinton does have a prominent difficulty -- a trustworthiness deficit, ABC's GREGORY HOLYK reports. Even with her overall lead, 44 percent of leaned Democrats say Sanders is more honest and trustworthy, vs. 38 percent who pick Clinton. http://abcn.ws/1TSvphV

IN THE NOTE'S INBOX

NEW SUPER PAC AD CASTS CARLY FIORINA AS 'AMERICA'S IRON LADY'. The Super PAC support Carly Fiorina's presidential bid has released a new digital ad casting the Republican candidate as America's Margaret Thatcher. "Thatcher was the original Iron Lady," a slate at the top of the ad reads before showing video of Thatcher rallying Britain. "Say hello to America's Iron Lady," the next slate reads, then cutting to video of Fiorina from this week's GOP debate. "Talking tough is not the same as being strong. And to wage war we need a commander in chief who has made tough calls in tough times and stood up to be held accountable over and over," Fiorina says in the ad. ABC's JORDYN PHELPS notes the ad, which will be targeted to early voting states, also includes sound of Fiorina quoting Thatcher, as she often does from the stump. WATCH HERE -- http://bit.ly/1ObECUq

TODAY ON THE TRAIL with ABC's SHUSHANNAH WALSHE: We won't see Hillary Clinton and Martin O'Malley today as they continue to prep for the debate. Bernie Sanders is on Capitol Hill this morning for votes. Ted Cruz continues his 12 state tour. Today he holds a rally in Mechanicsville, Virginia before heading to Kennesaw, Georgia for an evening event. Marco Rubio, Ben Carson, Carly Fiorina, and Mike Huckabee are all in Iowa. Rubio holds a town hall in Dubuque this afternoon before leaving the first caucus state to head to Joplin, Missouri for a late afternoon rally. Carson stops this morning in Storm Lake before holding an afternoon town hall in Orange City. This evening he holds a rally Sioux City. Fiorina holds a town hall this afternoon in Clinton City before heading to Dubuque for an employee town hall and tour of McGraw-Hill Education. This evening she is in Davenport for a Christmas reception. Huckabee has a busy day with five events starting this morning in Emmetsburg before heading to Algona for a tour and town hall. New Hampshire is much quieter today as Lindsey Graham is the only candidate in town. This afternoon he is in Merrimack for a Nanocamp business tour before attending the Stafford Christmas Party in Dover this evening.

THE BUZZ

with ABC's VERONICA STRACQUALURSI and PAOLA CHAVEZ

DEMOCRATIC PRESIDENTIAL CANDIDATES: WHERE THEY AGREE AND DISAGREE ON CLIMATE CHANGE. This month in Paris, the United States along with nearly 200 other countries signed arguably the most sweeping international environmental agreement in history. Republicans were quick to dismiss it. In stark contrast, all three Democratic presidential candidates argue that climate change is an urgent and serious threat facing the country and demand quick action. Former Maryland Gov. Martin O'Malley and Bernie Sanders, in fact, go so far as to say that the country has a "moral obligation" to curb the effects of toxic greenhouse gases. But there are also key differences between them. ABC's MARYALICE PARKS takes a closer look at the three Democratic proposals side by side: http://abcn.ws/1NWamec

TRUMP SAYS 'GREAT HONOR' TO GET COMPLIMENTS FROM 'HIGHLY RESPECTED' PUTIN. Republican presidential candidate Donald Trump seems to have a new fan in his corner -- Vladimir Putin -- and the real estate mogul thinks it was a "great honor" to get compliments from the Russian leader. Speaking to ABC News earlier Thursday, the Russian leader said Trump is "a very colorful person. Talent, with any doubt. According to ABC's JOHN SANTUCCI, Trump tells ABC News in a statement that "it is always a great honor to be so nicely complimented by a man so highly respected within his own country and beyond." http://abcn.ws/1Qw2GRY

NOTED: EXPERTS DOUBT TRUMP'S PLAN TO EXECUTE COP KILLERS WOULD PASS MUSTER. GOP presidential candidate Donald Trump reiterated his call for creating a mandatory death penalty for anyone who kills a police officer in the United States, despite possible constitutional conflicts. "Our police officers have been treated horribly," Trump told ABC News aboard his private jet Wednesday. "They've been tremendous supporters of me. ... I have great, great feelings for the police of this country. They do a great job and, yes, I want the death penalty for anybody that kills a police officer." Pressed on how he would accomplish it, Trump said he would "work with the states if I have to; if we can do it on a federal basis, we'll do it on a federal basis." ABC's JOHN SANTUCCI has more. http://abcn.ws/1maGiRn

BEN CARSON CANCELS TRIP TO AFRICA, ISRAEL DUE TO 'SIGNIFICANT SECURITY CONCERNS'. Republican presidential candidate Dr. Ben Carson is canceling his foreign policy trip to Israel and Africa, which was set for the end of December. Carson's campaign said the decision to cancel the trip was made Wednesday afternoon. "We decided yesterday afternoon to cancel based on significant security concerns that we had to take seriously," Communications Director Doug Watts told ABC News. "We just made a decision based on pertinence." Watts said there were threats, but would not comment on the nature of them. He noted that the campaign did not "make this decision lightly." ABC's KATHERINE FAULDERS reports Carson's week-long planned foreign policy trip was focused in Africa, where he was scheduled to visit the countries of Nigeria, Kenya and Zambia, with a brief stop in Israel before the Africa swing. http://abcn.ws/1RU9IQ5

OBAMA WILL BE 'VISIBLE CAMPAIGNER' IN 2016, WHITE HOUSE SAYS. Unlike the 2014 midterm election cycle when President Obama was rarely seen campaigning for fellow Democrats, the White House says that 2016 will be different. The president will be a "visible campaigner" next year, stumping for the Democratic presidential nominee and other Democratic candidates, senior Obama administration officials told reporters Thursday. The officials also did not rule out the possibility that the president endorses in the Democratic presidential primary in which his former Secretary of State, Hillary Clinton, remains the heavy favorite, ABC's ARLETTE SAENZ notes. http://abcn.ws/1Mka2Ax

ANALYSIS -- DONALD TRUMP AND BERNIE SANDERS: THE TWO BIG PHENOMENA OF THIS ELECTION. It is the week of debates. And the beginning of the celebration of the holidays. To give homage to Charles Dickens' "A Christmas Carol," ABC's MATTHEW DOWD looks at the ghosts of the Debate Past, pause for the Present, and look ahead to the ghosts of the Debate yet to come (ABC News hosts a Democratic debate this Saturday in New Hampshire). http://abcn.ws/1QvgYCy

IN CASE YOU MISSED IT

NEW HAMPSHIRE'S DRUG EPIDEMIC TAKES CENTER STAGE. In a poll conducted by ABC Manchester affiliate WMUR-TV in October, New Hampshire residents named drug abuse the top issue facing the state, the only time in the past seven years the economy and jobs haven't occupied the top spot. ABC'S BRAD MIELKE reports In 2013, New Hampshire saw 192 overdose deaths, which is expected to double two years later. http://abcn.ws/1Nzy0JH

WHO'S TWEETING?

@JebBush: Does Donald even know Putin backs Iran/Assad? Does he care? We must stand up to Putin not coddle him #ChaosCandidate

@JesseFFerguson: Friday's Union Leader op-ed from @HillaryClinton - "My plan to bolster homeland security and defeat ISIS" http://www.unionleader.com/Another-View-Hillary-Clinton-My-plan-to-bolster-homeland-security-and-defeat-ISIS ...

@JamesPindell: Ground Game | Why 'Clinton Country' has uniquely been so good to Sanders, Q & A with DNC chair - http://eepurl.com/bKiCKj #fitn

@JohnJHarwood: Old calculus says terror focus hurts @HillaryClinton as woman Dem. But she starts w/polling edge over Rs on issue: http://www.nytimes.com/2015/12/18/us/politics/shift-to-security-disrupts-us-presidential-race.html?smprod=nytcore-ipad&smid=nytcore-ipad-share ...

@ryanstruyk: At this time in history: A national USA Today/Gallup poll in 2007. Clinton 45, Obama 27