Sen. Bernie Sanders made good on his threat to sue the Democratic National Committee on Friday afternoon, as the fight over a data breach committed by his campaign escalated into a broader battle with the Democratic Party’s establishment.

Sanders’ suit seeks to regain access to a voter database that his campaign says is crucial to his ability to raise funds and reach voters. The DNC cut off the campaign’s access Thursday after it was discovered that Sanders’ campaign staffers had improperly looked at private voter files that belonged to Hillary Clinton’s campaign.

The Sanders suit claims that its contract to use the database cannot legally be terminated without 10 days' written notice, that its access to Clinton’s data was “inadvertent,” and that the larger problem is the fault of the third-party vendor, NGP VAN, which left the data vulnerable.

“The Campaign should not be punished for the carelessness of the DNC and its third-party vendor,” Sanders’ attorneys Benjamin J. Lambiotte and Sean C. Griffin wrote in the suit, filed just before the close of business.

The attorneys argued that the Sanders campaign is “hamstrung” without the voter database.

“The financial damage caused by the loss of donations is estimated to be approximately $600,000.00 a day,” they wrote. “However the damage to the Campaign’s political viability, as a result of being unable to communicate with constituents and voters, is far more severe, and incapable of measurement.”

Here's a link to the suit: https://berniesanders.com/wp-content/uploads/2015/12/Bernie2016vDNCComplaint.pdf