(CN) - The campaign of Sen. Bernie Sanders followed through on its threats to sue the Democratic National Committee for the "unwarranted, unilateral suspension" of a crucial voter database late on Friday.
The lawsuit estimates the committee's drastic action has cost his campaign $600,000 a day, and damages his presidential aspirations in ways that are "incapable of measurement."
One day shy of the last Democratic debate of the year, Sanders' campaign manager Jeff Weaver issued a blistering statement accusing the committee of "actively attempting to undermine our campaign" in favor of front-runner Hillary Clinton.
A bug in a voter-file program run by the Democratic Party's vendor NGP VAN set the stage for this feud on Wednesday, when a firewall preventing the candidates from accessing each others' databases collapsed for 45 minutes.
DNC chair Rep. Debbie Wasserman-Schultz said the Sanders campaign's national data director Josh Uretsky "inappropriately accessed" the Clinton campaign's voter-targeting data during this window.
The committee cut off the Sanders campaign's access to the database hours after the Communication Workers of America and Democracy for America endorsed the candidate on Thursday.
Calling the director's conduct "unacceptable," Weaver said that the Sanders campaign fired Uretsky, and that an investigation into other staffers who allegedly participated is ongoing.
The lawsuit by the campaign's corporate vehicle, Bernie 2016, Inc., denies that there was anything other than "inadvertent access" to Clinton's data.
"Even assuming, arguendo, that the DNC could prove that campaign staff intentionally accessed any disclosed information, such access would not amount to a breach of the agreement, or give the DNC cause to suspend or terminate the agreement," the 11-page complaint states.
The committee's agreement requires written notice allowing candidates to cure any breach within a 10-day window before terminating the contract, according to the lawsuit.
Weaver also took swipes at vendor NGP VAN for its "dangerous incompetence," revealing that the database had "serious failures" in the past.
The Sanders campaign privately reported a similar incident to the DNC months ago without going to the press, he added.
Echoing Weaver's critique, the lawsuit blames the incident on a "critical security flaw" by the committee's vendor.
"The DNC should not be permitted to tip the scales of the Democratic presidential primary without clear justification and contractual cause," the complaint states. "The fairness of this pivotal national election should not be compromised because of security flaws introduced by the DNC and its vendor."
Wasserman-Schultz has come under fire for scheduling half as many presidential debates for the Democrats as the GOP scheduled for its candidates.
Longshot Democratic candidate Martin O'Malley joined Sanders in criticizing the timing of Saturday's debate, which falls on the same night as a football matchup between the New York Jets and Dallas Cowboys on the weekend before Christmas.
The Clinton and O'Malley campaigns did not immediately respond to email requests for comment, but Clinton's press secretary Brian Fallon took to Twitter to slam the lawsuit.
"There is a word for this in Brooklyn: chutzpah," he wrote, referring to the borough where Sanders was born and Clinton runs her campaign headquarters.
Larry Lessig, a Harvard Law School professor who is also running for president on a platform of campaign-finance reform, predicted that a lawsuit by the Sanders campaign would succeed.
"Such a suit should certainly win," Lessig said in an email. "The actions of NGP VAN are outrageous. Even if there was a violation, the punishment must fit the crime. This is cutting the oxygen to the Sanders campaign. It is completely inappropriate."
After being shown the lawsuit, Lessig reiterated that view in a phone interview.
"They certainly didn't comply with the terms of the contract," he added, referring to the party leaders.
In October, Lessig complained to Politico that the Democratic committee shut him out of a prior debate even though one poll showed he had the 1 percent electoral support required for his participation.
Although he declined to draw any comparisons with that experience, he added: "I think people are making this link that there's this desire to bend the rules and bend the practices to protect the presumed nominee."
Bernie 2016 is represented by Washington-based lawyer Benjamin Lambiotte, of the firm Garvey Schubert Barer.