On Sunday night, after umpteen interviews about rounding up 41 votes to filibuster Supreme Court nominee Neil Gorsuch, Senate Minority Leader Charles E. Schumer (D-N.Y.) called into the weekly “Ready to Resist” call organized by MoveOn and other progressive groups. He waited his turn. MoveOn’s Anna Galland reported that Sen. Jon Tester (D-Mont.) just joined the filibuster. Heather McGhee, the president of Demos, praised Schumer for listening to activists.

“I want to thank Chuck Schumer for showing the backbone to do what Democrats demand he do at this moment,” McGhee said.

When his turn came, Schumer told the tens of thousands of people listening in that they were helping build a real resistance to Gorsuch. He compared their work to his youthful campaigning for Sen. Eugene McCarthy — nobody thought they could win, and they brought down a president.

“I’ve never seen such dedication and action in the grass-roots communities since the Vietnam War, until this year,” he said. “And you’re really helping us.”

Just weeks ago, it was far from certain that Democrats would muster 41 votes to filibuster Gorsuch. That they have secured 44 votes to do so — retaining all but four members of their caucus — is the latest victory for activists who have rallied to drive the party toward total opposition of the Trump administration.

“People are in a mood for a principled stance, not for backroom deals,” said Ilyse Hogue, the president of NARAL, which led a coalition of progressive groups under the slogan #WeObject. “We were told it was unwinnable, but we didn’t really care about the political math. Women needed this fight to be fought.”

Hogue’s wing of the campaign began Feb. 21, when she emailed friends on the left to ask why there was no coherent, people-powered opposition to the Gorsuch nomination. At that time, several Senate Democrats were holding off on opposing Gorsuch, on the theory that confirming him would keep the court at its post-2005 status quo — four conservatives, four liberals and one right-leaning swing vote. Tempting Republicans to “nuke” the filibuster would mean that, in the event that a liberal retired or died before 2021, Democrats would have no way to block a conservative pick.

But in the past month, activists and Democratic senators drank from the same well of cynicism. The blocked nomination of Merrick Garland was itself a nightmare scenario and an abandonment of a political norm. Few Democrats came to think that the filibuster would survive if Democrats rolled on the Gorsuch fight, and Republicans, later, had a clean shot at remaking the court.

“The idea that you can actually reason with these people or that they’re not going to use every tool to get what they want has been debunked,” Hogue said.

Despite a hefty ad campaign promoting Gorsuch, Democrats felt little political pressure to support him. After his hearings, Gorsuch had positive poll numbers, but many voters still said they didn’t know him. And as they came out to oppose him, Democrats highlighted issues on which their position, even in red states, was more widely accepted than Gorsuch’s. “With Judge Gorsuch on the bench, I am deeply concerned that dark money will continue to drown out the voices and votes of citizens, the court will stand between women and their doctors, and the government will reach into the private lives of law-abiding Americans,” Tester said.

“Gorsuch did himself no favors in that hearing,” said Ian Millhiser, a senior fellow at the Center for American Progress. “He mansplained fairly basic concepts to women senators. He pushed way too hard on the ‘I’m not going to express a view about anything, ever’ fallback — much harder than previous nominees. And then, after the Supreme Court unanimously overturned one of his opinions, he defended himself by misrepresenting his own opinion. Plus he seemed physically incapable of putting on the kind of performative humility that literally every other person nominated for a Senate-confirmed job puts on during their hearing.”

In the Sunday night phone call, Schumer seemed ready to endorse every argument activists made. When one suggested that the investigation into the Trump campaign’s possible ties to Russia should delay the vote, Schumer didn’t fully disagree.

“Unfortunately, the Constitution doesn’t say that when the president’s under investigation he loses the ability to do this.”