In a major victory for underdog Democratic presidential candidates Martin O’Malley and Bernie Sanders, two top officials with the Democratic National Committee publicly broke with the party Wednesday night, calling for changes to the debate process that the candidates have advocated.

In a joint statement posted to Facebook, Hawaii Rep. Tulsi Gabbard and former Minneapolis Mayor R.T. Rybak, both vice chairs for the DNC, called for increasing the number of debates and said a so-called exclusivity clause was a “mistake.”

“As vice chairs of the Democratic National Committee, we are calling for several more debates than the six currently scheduled, and withdrawing the proposed sanctions against candidates who choose to participate in non-DNC sanctioned debates,” they wrote.

So far, the DNC has not budged. At a breakfast with reporters Thursday in Washington sponsored by the Christian Science Monitor, DNC Chair Debbie Wasserman Schultz made it clear she had no interest in changing the rules. “We’re not changing the process. We’re having six debates,” she said. “The candidates will be uninvited from subsequent debates if they accept an invitation to anything outside of the six sanctioned debates.”

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The committee this year scheduled only six debates and instituted a controversial rule that punishes candidates who participate in unsanctioned debates by barring them from future official events. O’Malley, a former Maryland governor, and Sanders, a senator from Vermont, have complained loudly about the clause, accusing the DNC of writing the rule to protect front-runner Hillary Clinton.

O’Malley in particular has practically gone to war with his own party. In addition to a fury of tweets and interviews on the debate rules, O’Malley devoted almost his entire speech at the DNC’s summer meeting two weeks ago in Minneapolis to hectoring the committee. His campaign has helped organize a protest outside the DNC headquarters planned for next week, and they’ve even threatened legal action.

“I assume they’re circling the wagons around the inevitable front-runner as her descent continues,” O’Malley told MSNBC’s Chris Hayes Wednesday.

Supporters of Sanders, meanwhile, have also mobilized thousands of grassroots supporters to lobby the DNC for more debates

For her part, Clinton recently suggested she was open to participating in more debates. ”I am open to whatever the DNC decides to set up,” she told reporters in New Hampshire last week.

Outside of their camps, there has been growing discontent behind the scenes, and Rybak openly bemoaned the rules in conversations with delegates at the Minneapolis meeting. On Monday, former DNC Chair Howard Dean told The Washington Post the rule was “not right” and should be scrapped.

But the message from Gabbard and Rybak is by far the biggest and most public call yet, and will likely force the DNC to respond. O’Malley senior strategist Bill Hyers hailed the vice chairs’ statement, saying they “voiced what Governor O’Malley has said all along.”

“We are the party that represents democratic principles, openness and transparency, and ensuring that all people, regardless of who they are or where they are from, have a level playing field and equal opportunity,” Gabbard and Rybak wrote. “By limiting Democratic debates to just six, more people will feel excluded from our political process, rather than included.”