MANCHESTER, N.H. — This is the war Democratic presidential candidate Bernie Sanders’ progressive coalition was ready for.

There is nothing more uniquely suited to the Vermont senator's coalition of old-school liberal and newfangled digital lefties than Friday’s high-octane fight with the Democratic National Committee after the Sanders campaign was caught rifling through proprietary Hillary Clinton data made available through a DNC vendor’s software glitch. For many Democrats, Friday posed a real conundrum: How much punishment did the Sanders campaign deserve, and how deep into the primary could the DNC wade?

For the progressive left backing Sanders, there was no such dilly-dallying. Whatever happened, they say — and they do understand something happened — the DNC decision to freeze the Sanders campaign out of the all-important voter file was about the establishment hammer coming down hard on an insurgency it just could not shut down until now. It was the latest in a string of moves by the Democratic mainstream to put an end to the Sanders campaign once and for all, they said in Internet postings and emails among themselves.

"We've all been around long enough to see how the establishment fights back when a progressive grassroots effort rises up,” said Neil Sroka, communications director at Democracy For America, the progressive group that backed Sanders just this week.

“Regardless of how the data was moved, it's actually fundamentally immaterial,” Sroka said. “The answer to this problem cannot be ‘shut this campaign down.’”

DFA sprang into action Friday morning as news of the DNC suspension of Sanders’ field efforts spread. The group blasted three emails to its member base calling on them to sign an online petition urging DNC leaders to change their minds. The message was not subtle.

“It seems like the DNC is doing all it can to blunt the momentum of Bernie's campaign,” wrote former Clinton Labor Secretary Robert Reich in one DFA missive.

The effort was a great success, say DFA leaders. In the first 90 minutes of the petition drive, more than 25,000 people signed up. By the end of the day, 50,000 had signed on. A petition at MoveOn, launched without any conversation with DFA, gathered nearly 250,000 signatures by the end of Friday.

Other groups like the Working Families Party, which also backed Sanders recently, joined in with almost the exact same message.

“If the leaders of the Democratic Party are truly conducting a fair primary process, they'll take their thumbs off the scale and restore Senator Sanders' data access right away,” Dan Cantor, national director of the WFP, said in a statement.

National Nurses United, one of the unions backing Sanders, also activated its members, planning a protest outside DNC chair Debbie Wasserman Schultz’s office Saturday morning. Its hashtag: #StormTheDNC.

It was a coordinated attack on the DNC from Sanders’ progressive base, but behind the scenes there was no real coordination. Progressive groups were more than ready to fight the DNC, and fight it for being unfair to Sanders.

“There is always a concern that when a progressive rises up and starts being successful there's going to be an effort to tamp that down,” said an aide with one of the groups which joined the fray Friday.

Throughout his campaign, Sanders has relied on this latent lefty distrust of the mainline Democratic party to fuel his campaign’s grassroots machine. On the stump, Sanders boasts about not being the candidate of the establishment and revels in his lack of endorsements from prominent elected officials.

His campaign stayed largely out of the fray the last time his supporters kicked up a storm about the DNC. Earlier this year, when Sanders was on the rise in the polls and progressives were going to war with Wasserman Schultz over the debate calendar, top Sanders aides stayed out. (Tad Devine, Sanders’s senior strategist, told Time the debate over debates was a “distraction.”)

Sanders’s supporters never stopped seeing him as the candidate who scares the establishment the most. That’s why, progressive activists said, they all moved in the same direction when they saw what the DNC had done: It was obvious to all of them who the wronged party was.

“Literally there was no conference call,” Sroka said. “We didn't even have to talk to each other. This is the constant worry, that a progressive is going to rise up, and the establishment is going to knock them down.”