Update: The Bernie Sanders campaign has now threatened legal action against the Democratic National Committee with Sanders’ top aide Jeff Weaver saying, “They are not going to sabotage our campaign.”

On Thursday, Democratic presidential candidate Senator Bernie Sanders received two high-profile endorsements from groups aligned with the Democratic Party. The Communication Workers of America (CWA), one of the country’s largest unions with 700,000 members, endorsed Bernie Sanders for president. Million-member strong Democracy for America, an activist group led by Hillary Clinton supporter Howard Dean, also endorsed Sanders after a vote by its membership.

The endorsements come after a virtual mainstream media blackout of Senator Sanders who, despite polling ahead of Donald Trump, has received 23 times less coverage. Recent polling also show Senator Sanders within striking distance of Hillary Clinton in Iowa and maintaining his lead in New Hampshire.

These dynamics setup a tough and crucial debate between Sanders and Democratic establishment favorite Hillary Clinton for Saturday night. That was until today, when the Democratic National Committee (DNC) — led by Hillary Clinton-supporter Congresswoman Debbie Wassmerman Schultz — attacked the Sanders campaign by claiming the Sanders campaign violated DNC rules by accessing the Clinton campaign’s data via the DNC system known as the NGP-VAN system.

The charges against the Sanders campaign are incredibly dubious. The DNC has continually failed to provide a functional and secure database for all the campaigns involved and admits that the inappropriate access could only occur due to a “glitch” in the DNC’s system.

The Sanders campaign staffer accused of violating the rules, now fired, told CNN that he was not trying to access Clinton’s data but evaluating how the security glitch affected Sanders own data, as it had on a previous occasion:

“This wasn’t the first time we identified a bad breach,” he said, confirming to CNN that the Sanders campaign reported another breach to the DNC in October. “We reported it to them. They thanked us for reporting it and they told us the breach had been closed.”

“In retrospect, I got a little panicky because our data was totally exposed, too,” Uretsky said of how he handled the latest breach. “We had to have an assessment, and understand of how broad the exposure was and I had to document it so that I could try to calm down and think about what actually happened so that I could figure out how to protect our stuff.”

Rather than handle the situation with its faulty system internally as the DNC had previously, the DNC pounced and smeared the Sanders campaign for committing some transgression and followed up by blocking the Sanders campaign from accessing the NGP-VAN system until the DNC is satisfied. Being blocked from NGP-VAN could cripple the Sanders’ campaign field operation to get out the vote for the primaries.

The DNC was already under fire for favoring Clinton by hiding the presidential debates on off-prime time nights. Now it appears the DNC wants to poison the upcoming debate with shaky claims of impropriety to help their favored candidate.

A petition has been started at MoveOn.org demanding that DNC chairwoman Debbie Wassmerman Schultz reinstate the Bernie Sanders campaign’s access to NGP-VAN.