It was just four years ago when 31 Senate Democrats signed a joint, bipartisan statement in support of preserving the legislative filibuster for the indefinite future. In 2021, the pace at which many of those same Democrats are changing their minds is extraordinary.

In recent months, Sens. Cory Booker (D-N.J.), Amy Klobuchar (D-Minn.), Bob Casey (D-Pa.), Sherrod Brown (D-Ohio) and Ed Markey (D-Mass.) have all called for institutional reforms, abandoning their support for the 2017 joint statement. This week they were joined by Democratic Virginia Sens. Tim Kaine and Mark Warner, both of whom signed the pro-filibuster letter four years ago, and both of whom now support reforming the Senate’s rules, agreeing that “the supermajority rule of the Senate is preventing our country from doing important work right now.”

This week, Senate Majority Whip Dick Durbin (D-Ill.) added his voice to reform efforts, arguing on the chamber floor that the filibuster is “making a mockery of American democracy.” Reflecting on the broken status quo, the Senate’s #2 Democrat added, “This is what hitting legislative rock bottom looks like.”

And what about President Joe Biden, who’s long expressed skepticism about amending the rules of the institution in which he served for 36 years? All of a sudden, he’s starting to hedge, too.

President Joe Biden said Tuesday that he supports overhauling the Senate filibuster to require the minority to talk on the floor to block legislation, endorsing a momentous change that some progressives say could help advance his agenda. Biden said senators should have to “work for the filibuster” when ABC News’ George Stephanopoulos asked him whether he will have to choose between preserving the 60-vote rule and advancing his agenda.

“I don’t think that you have to eliminate the filibuster. You have to do what it used to be when I first got to the Senate back in the old days,” Biden said in an interview excerpt released last night. “And this is — a filibuster, you had to stand up and command the floor. You had to keep talking alone.”

Reflecting on the bigger picture, the president added, “It’s getting to the point where democracy is having a hard time functioning.”

As is always the case, the details matter. What Biden seemed to be endorsing was old-school “talking filibusters” in which senators delayed votes by speaking for hours on end. Sen. Joe Manchin (D-W.Va.), another Democrat who’s expressed opposition to ending filibusters, expressed support for a similar change last week.

The trouble is, returning to “talking filibusters” would not, in and of itself, fully address the problem. It would depend entirely on how the change was implemented. (Bloomberg’s Jonathan Bernstein has written for many years about the drawbacks of the idea.)

But what matters more is the other part of Biden’s comments to ABC News: “It’s getting to the point where democracy is having a hard time functioning.”

Exactly. That’s what matters. The specifics on Senate procedures and how members may or may not hold the floor can be worked out later. The important thing for Democratic leaders — and right now, there’s no more visible leader than the sitting American president — is to recognize is that the status quo in the Senate is untenable.

Once there’s agreement on this core point, policymakers can work out the details later. It changes the debate from whether to fix the Senate to how to fix the Senate.

Is it any wonder Senate Minority Leader Mitch McConnell (R-Ky.) seems awfully nervous?