How Berned Is Bernie Sanders By The DNC Data Breach? A lot. At least for now.

UPDATE (Dec. 19, 10:04 a.m.): The Bernie Sanders campaign and Democratic National Committee reached a deal Saturday to restore the campaign’s access to the party’s data, though the DNC says it “will continue to investigate to ensure that the data that was inappropriately accessed has been deleted and is no longer in possession of the Sanders campaign.”

Check our our live coverage of the Democratic debate.

In New York, they say, money is power. In Washington, it’s who you know. If you’re running for president, it’s who you’re hoping to get to know that matters. A multi-million-dollar industry has sprung up around collecting information on potential voters; that’s how candidates know where to send chummy, “hello friend!” emails and whose dinner hours to interrupt with a knock on the door or a phone call.

Voter files are the informational blueprints that campaigns use to build their coalitions. The massive voter file collected by the Democratic National Committee and managed by the independent firm NGP VAN is basically the informational teat from which all successful modern Democratic campaigns must suckle. So when the Democratic National Committee announced on Friday that it had barred the Bernie Sanders campaign, at least temporarily, from accessing its voter file, all hell broke loose in the political data universe.

The fracas began on Wednesday morning, with the crash of a software firewall that is supposed to prevent campaigns from seeing the voter data compiled by rival candidates. (All the Democratic presidential campaigns have access to the DNC data, and can then add their own information and analysis to the database.) The crash allowed members of Sanders’s staff to view proprietary voter lists of the Hillary Clinton campaign, including, according to news reports on Friday, information on voters less inclined to support the former secretary of state in the critical early states of Iowa and New Hampshire.

To punish the Sanders campaign for the breach, the DNC said the campaign could not have access to the party’s voter data. (The Sanders campaign fired a staffer involved in viewing the Clinton data, but said the punishment was unwarranted.)

What exactly does this deprivation of informational access mean for the day-to-day operation of the Sanders campaign?

A former Obama campaign data operative I talked to called it “a pretty devastating loss,” and others in the political data world said much the same. (People in that ever-so-analytical community are abuzz, but many declined to talk on the record.)

The DNC files are filled with public information — no private information, à la credit card company hacks, would have been compromised here — that’s been gathered from various secretaries of state offices across the country. Those files contain names, addresses, elections voted in, and in some states, date of birth and gender.

Without access to these files, the Sanders campaign’s ability to canvass voters in a targeted manner — go to this house, but not that one — is lost, as are its capabilities to create a tailor-made phone list to contact voters who are more likely to #FeelTheBern. It basically means Sanders staffers have to campaign like it’s 1999, and in this case, being old school is nothing to brag about.

Matt Klaber, a former developer at NGP VAN who also worked as the data director for John Edwards’s New Hampshire operation in 2008, said the campaign was dealing with a “pretty significant” loss, though he said that it’s possible the Sanders organization could work around the problem in the short-term.

“There might be lists of people to call that are still fresh,” Klaber said, noting the campaign could have saved or printed lists outside the NGP VAN system.

But the long-term effects are alarming enough that the Sanders campaign filed a lawsuit in federal court on Friday seeking to re-gain access to the DNC’s voter file, saying that the committee was “attempting to undermine” its campaign, and that the organization “continues to hold our data hostage.”

“Plaintiff is sustaining irrrepable [sic] injury and financial losses,” according to the Sanders campaign’s complaint, “that are incapable of precise calculation, but exceed $600,000.00 per day.”

The “our data” phrasing by the Sanders team might seem antithetical to the idea that campaigns essentially rent the DNC’s list for their purposes, but there are a couple of categories of data the Sanders team would be dealing with in the NGP VAN system. The big kahuna, the voter file that the firm has had a contract to manage since 2007, is the property of the DNC. Campaigns gather information from voters that serve to enrich this file — who a caller says they’ll vote for or whether a landline number is dead are seen as valuable tidbits — and they agree to update the system after the campaign so that future candidates can use it.

But what probably angers Sanders and his people the most is being locked out of information they’ve collected on potential Sanders volunteers. If a person whose door is knocked on says they’d like to volunteer for the campaign, that’s quite a boon, and the campaign would store that information away in the system. When staffers were locked out of the NGP VAN system, they would have lost access to these files, Klaber said.

As for the breach itself, he said any developer expects bugs to happen, but said he had never seen one like this.

“In my almost seven years there,” he said, “this kind of thing didn’t happen.”