They just don't care.
"The filibuster is such a silly, non-intuitive tactic that most people don't even believe it exists," Markos Moulitsas, founder of the liberal blog DailyKos.com, told CNN in an email.
Inside the Senate, some red-state Democrats and longtime institutionalists have fretted that mounting an all-out battle to stop Gorsuch will hurt the party's chances of winning future fights and further degrade the more deliberative chamber of Congress. The 'nuclear option' would lower the bar from 60 senators needed to break a filibuster to 51, and Republicans currently control the chamber with a 52-48 margin.
But off Capitol Hill, Democrats -- from Washington insiders to progressive activists across the country -- are sick of hearing about those precautions.
Fueled by the base's anti-Trump energy, Democrats across the spectrum don't want to hand Trump any easy victories. They are insisting on showing Republicans that blocking Merrick Garland's Supreme Court nomination in President Barack Obama's final year won't go without retaliation.
And they see the filibuster -- which McConnell could erase at any point -- as a gun with no ammunition.
"The filibuster is effectively gone. If you don't filibuster Gorsuch, McConnell will just get rid of it next time," said Adam Jentleson, a former Harry Reid aide who's now a senior strategic adviser for the Center for American Progress Action Fund.
Many Democrats were frustrated by senators' initial openness to supporting Gorsuch, but the nominee bungled the opportunity to win many of them over with what Democratic senators viewed as dismissive answers to questions during his confirmation hearing and to written follow-ups, Jentleson said.
Contrary to some institutionalists' hopes, McConnell would be even more likely to invoke the nuclear option to get the next Supreme Court nominee confirmed, he argued.
"Next time, the balance of the court would be at stake, so the motivation to go nuclear is even stronger. It goes both ways," he said. "It's false to say Democrats don't care. But I think it's just not their choice."
"Reid put up with years and years of incredible amounts of obstruction, and pressure from his base, before he finally went nuclear," Jentleson said. "McConnell, by sort of signaling he's going to do it beforehand -- literally the very first opportunity to go nuclear, he's pulling the trigger."
Sen. Chris Coons, D-Delaware, was the 41st Democrat to pledge to oppose Gorsuch, guaranteeing a filibuster. He told CNN's Wolf Blitzer that he is open to negotiating with Republicans to find an agreement on avoiding the nuclear option -- so long as the GOP doesn't invoke it on the next confirmation battle.
"I said, 'I will vote against closure unless the Republicans and Democrats in the Senate can somehow find an agreement that is trustworthy and reliable, where on the next Supreme Court nominee they won't change the rules and we will have input, and a more confirmable, consensus nominee will be put in front of the Senate,'" Coons said. "I'm not saying that I'm insisting that we force the Republican majority to break the rules. That's a choice they're going to have to make."
Like Coons, Sen. Patrick Leahy, D-Vermont, publicly agonized over his decision. But on Monday, he said he would filibuster Gorsuch, saying he "cannot vote solely to protect an institution."
Campaigning Friday in New Jersey, Democratic National Committee chair Tom Perez and deputy chair Keith Ellison, a Minnesota congressman, both called for a filibuster of Gorsuch, knowing it would likely lead McConnell to invoke the nuclear option.
"If you do not have enough support, we should not change the rules for you," Ellison told Democrats in Asbury Park. "We should change the nominee."
Perez made the point again in a statement Monday, after it became clear Democrats would filibuster Gorsuch.
"It's plain and simple: Gorsuch has not earned the votes in the Senate to join the Supreme Court," he said. "Republicans can't fix Gorsuch by changing the rules. They need to change the nominee."
Other Democrats directly called for the filibuster's elimination, taking the long view that it could help the party if and when it regains Senate control.
Moulitsas mocked the hand-wringing about the loss of the 60-vote threshold, saying "it's mostly been a tool used by conservatives" and noting that the Heritage Foundation and Sen. Ted Cruz of Texas had talked about keeping an eight-seat Supreme Court through the entire tenure of a President Hillary Clinton before the election.
"Majority rule means accountability to the voters," he said. "It also means that elections really do matter, since the losers can't hide behind parliamentary maneuvers. So if McConnell really has the votes to kill it, good riddance."