More than 30 former top Senate Democratic aides call for changes to the filibuster rules.

Hoping to build momentum for a change in Senate filibuster rules, more than 30 former chiefs of staff to Democratic senators have written an open letter calling for “repeal or reform” of the procedural tactic they say no longer serves its original purpose.

The 31 signers of the letter, who worked for more than 25 current and former Democratic lawmakers, conceded that they and their former bosses had embraced the filibuster in the past. But they argued that the maneuver is now being abused as a blunt-force instrument to stall most legislation.

“Over the course of the past 20 years, the filibuster has put a chokehold on the Senate,’’ said the letter, to be published on the website of the anti-filibuster group Fix Our Senate. “Legislation is now routinely filibustered, transforming the Senate from a place of meaningful debate and progress into a legislative graveyard.”

The letter also said that the main arguments typically cited for maintaining the filibuster — that it fosters bipartisanship, protects minority rights and prevents wild swings in policy with changes in power — no longer hold true.

The filibuster, once used sparingly, was never intended to be a way for the minority to routinely block legislation by preventing bills from advancing, they wrote.

“Many of us stood shoulder to shoulder with our former bosses when they filibustered legislation, and it was a valuable tool,” said Eric Mogilnicki, a chief of staff to former Senators Edward M. Kennedy and Paul Kirk of Massachusetts. “But it shouldn’t be that overwhelming the filibuster is the only way to pass legislation.”

Mr. Mogilnicki organized the letter along with Drey Samuelson, once the top aide to former Senator Tim Johnson of South Dakota.

The former aides banded together on the issue after Senate Republicans in recent weeks blocked several top Democratic priorities through a filibuster, including a sweeping voting rights bill as well as bipartisan legislation to establish an independent commission to investigate the Jan. 6 assault on the Capitol by supporters of Donald J. Trump.

Like many Democratic senators who have backed the filibuster in the past, the aides said their views had evolved as the tool was increasingly employed to thwart critically needed legislation supported by a majority of senators. They conceded that eliminating or weakening the filibuster could lead to enacting laws they oppose.

“We know that repealing or reforming the filibuster rule will someday lead to policy outcomes that we deeply dislike, and that might have been blocked under current Senate rules,” the letter states. “But we believe in a Senate where the people’s business can be done.”

While support has grown among Democratic senators for abolishing the 60-vote threshold for advancing legislation, filibuster opponents in the party currently lack the minimum 50 votes that would be required to overturn the rule.