{{show_title_date || "Sanders, DNC campaign reach deal over voter files, 12/19/15, 10:00 AM ET"}}

Acrimony and uncertainty at the Democratic debate

Updated

MANCHESTER, New Hampshire — For the second time in a row, unexpected events have completely upended a Democratic presidential debate. When candidates met in Iowa a month ago, the Paris terror attack had taken place one day earlier, casting a somber mood on the event and forcing an unexpected focus on national security.

Here, ahead of Saturday night’s debate, the explosive revelation that Bernie Sanders’ campaign staffers improperly accessed sensitive information owned by the Hillary Clinton campaign has shaken up the field once again. The ensuing fallout, unfolding over a tumultuous 24 hours on Friday, included a complete cutoff of voter data to Sanders’ campaign, a federal lawsuit, and accusations of potential illegal activity — all before it was quickly resolved late last night.

While the immediate crisis has concluded, the acrimony and distrust it bred between the two leading Democratic presidential campaigns and the DNC, which referees the primary, will not be as quickly healed. Things were said that cannot be unsaid.

RELATED: Bernie Sanders campaign, DNC reach voter data deal

The data breach and ensuing controversy will overshadow any policy differences or political positioning heading into the debate, and cast a pall on its outcome, regardless of how much the candidates actually discuss the issue on stage.

All parties say they want to get back to the issues— but whether they do will be entirely up to them. Will Clinton, whose campaign has been unusually aggressive in targeting Sanders, go in for the kill and seek to end the primary now? Or will she try to rise above the fray, perhaps even borrowing a line from Sanders to say “the American people are sick and tired of hearing about” his damn data breach?

Perhaps more likely, she’ll follow the path charted by DNC Chairwoman Debbie Wasserman Schultz, who has praised Sanders as a man of integrity while saying his campaign served him poorly in an this egregious error.

And will Sanders, whom we have not heard from personally, cast himself as the aggrieved party and offer no peace? His campaign has used the DNC’s draconian response to the breach to rally supporters to their long-standing struggle with the party and called the data cutoff a death sentence. Or will Sanders take responsibility, even though his staff kept him in the dark about the breach, and offer a mea culpa?

Perhaps he will turn the issue around on the moderators by saying the American people want to talk about issues, not inside baseball matters like this.

The fact that any of these possibilities are as likely as the rest underscores how much the incident has roiled the primary, which was threatening to turn into a low-wattage hum as Donald Trump captivated attention on the other side of the aisle.

QUIZ: What’s changed since the last Democratic debate?

Not helping matters is the fact that the debate falls on a Saturday night, during the final weekend before Christmas. That’s led supporters of Sanders and underdog Martin O’Malley to accuse the DNC of trying to protect front-runner Clinton by scheduling the debates when fewer people would be watching. The DNC denies the claim, but has refused to budge on the scheduling or number of debates.

Still, the candidates will undoubtedly spend most of their on stage discussing more substantive fare.

Sanders had telegraphed all week that he is preparing to press Clinton on her hawkishness and her tendency to support regime change. “One of the areas that we’re going to focus on maybe a little bit more than we have in the past is the differences between Secretary Clinton and myself on foreign policy,” he said while campaigning in New Hampshire Monday.

Clinton seems eager to discuss that as well, confident her extensive foreign policy experience will trump Sanders’ purity. She even wrote an op-ed earlier this week in the state’s largest paper discussing her plan for ISIS. It was a major topic during the second Democratic debate in Iowa, but there is much more to be hashed out on military interventionism, which was the definitive issue of the 2008 Democratic primary.

At the same time, far more local issues are likely to be put front and center. Sanders has sought to differentiate himself from Clinton by coming out against a high-profile and controversial proposed natural gas pipeline that would run through New Hampshire. Clinton in July dismissed it as a “local issue,” but now that Sanders has taken a position, she may be forced to do so as well.

And all three candidates will likely be unable to avoid a minuscule labor dispute with outsize impact: A pension disagreement with just about a dozen employees at Manchester-based ABC affiliate WMUR, one of only two TV stations in the state, has roped in all three candidates and led the DNC to strip WMUR of its sponsorship of the debate.

RELATED: A good day for Bernie Sanders

Meanwhile, opiate addiction, which has become an epidemic in New Hampshire, is also likely to be a topic in the debate. All three candidates have discussed the issue and pledged to bolster public health and recovery programs, and curb law enforcement. It’s an issue many New Hampshire voters want to hear candidates weigh in on. A WMUR poll from October had the stunning result that New Hampshire voters found drug abuse as the single most important problem facing the state.

Saturday’s debate is critical for Sanders, as New Hampshire is the lynchpin in his campaigns’ strategy. His top official in the state acknowledge to MSNBC last week that it is a “must-win.” He had a bit of momentum thanks to some big endorsement Thursday, but that may have been swept away by the data breach.

It’s important for Clinton, too. A seasoned candidate on the debate stage, she seemed to stumble in the last one, perhaps out of overconfidence.

No matter what, however, the final Democratic debate of the year promises to be far more exciting and unexpected that it was shaping up to be just 48 hours ago.

Bernie Sanders, Debates, Hillary Clinton, Martin O'Malley and New Hampshire

Acrimony and uncertainty at the Democratic debate

Updated