WASHINGTON — Leading Senate Democrats increasingly see the Republican blockade against raising the federal debt limit as clear justification for changing the chamber’s filibuster rule, a long-shot effort that so far has lacked the unanimous support within their ranks it would need to succeed.
President Biden, who has sent mixed signals for months about whether he supports scrapping the filibuster, gave fresh momentum to the idea on Tuesday when he told reporters at the White House that it was a “real possibility” that Democrats could create an exception to the rules and allow the debt ceiling to be raised with a simple majority.
“It’s not right, and it’s dangerous,” Mr. Biden told business leaders on Wednesday about blocking the debt legislation through a filibuster.
With tensions rising, Senator Mitch McConnell, Republican of Kentucky and the minority leader, sought to defuse the debt fight on Wednesday by offering Democrats more time to find a resolution, putting off the prospect of an immediate showdown on the filibuster.
Top Republicans said part of his motivation for the move was concern about the threat of a federal default, along with a fear that Democratic holdouts against changing the filibuster might reverse course under pressure from within their party.
Any weakening of the filibuster would significantly reduce Mr. McConnell’s power to block the Democratic agenda. He suggested on the Senate floor on Wednesday that Democrats might be orchestrating the battle over the debt limit to undo the Senate’s signature procedural tactic.
“It’s not clear whether the Democratic leaders have wasted two and a half months because they simply cannot govern, or whether they are intentionally playing Russian roulette with the economy to try to bully their own members into going back on their word and wrecking the Senate,” he said.
Democrats say it is Mr. McConnell who has been wrecking the Senate with his reliance on the filibuster to thwart their plans.
Under longstanding Senate rules, any single member may object to ending debate on legislation, a practice known as a filibuster, which effectively stops a bill in its tracks unless proponents can muster a three-fifths majority — or 60 votes — to move it forward. In the 50-50 Senate, that means Democrats need at least 10 Republicans to join them in breaking a filibuster, on the debt ceiling measure or anything else.
Democrats, who discussed the prospect at a private lunch on Tuesday before Mr. Biden’s comments, say the Republican intransigence on the debt limit has provided the best argument yet for curbing the filibuster.
“More and more people are drawing that conclusion,” said Senator Richard J. Durbin of Illinois, the No. 2 Democrat. “I think people feel the supermajority on the debt ceiling is a bridge too far.”
Yet it is not clear whether enough lawmakers are drawing that conclusion. The chief impediment to changing the filibuster has been the resistance of the centrist Democratic senators Joe Manchin III of West Virginia and Kyrsten Sinema of Arizona, and there is no indication that they have changed their stance in response to the current debt limit drama.
They argue that the procedural weapon can foster bipartisanship and provide guardrails against extreme actions by either party. Mr. Manchin this week dismissed the idea of any change in the filibuster for the debt limit, but at the private luncheon on Tuesday, he and Ms. Sinema were silent on the matter. Mr. Manchin has also said the government must not be allowed to default.
Mr. Manchin reiterated on Wednesday that he remained opposed to overhauling the filibuster.
“I think I have been very clear,” he told reporters. “Nothing changed.” Ms. Sinema remained quiet on the issue.
Democrats urging a change in filibuster rules said they hoped the nature of the debt limit fight, with Republicans’ refusal to negotiate and widespread warnings of global economic calamity if the government defaults, would persuade the two Democrats that it was time to put aside their misgivings and act.
“Republicans are making the case more powerfully than I could a million times on the floor,” said Senator Richard Blumenthal, Democrat of Connecticut and a longtime filibuster opponent. “What they are doing is obstruction and utterly exposes the filibuster. And it is not just inconvenience. It is desperately dangerous.”
Democrats could change the rules through a series of floor maneuvers with the votes of all 50 of their members and the tiebreaking vote of Vice President Kamala Harris. They say any carve-out for the debt limit would apply specifically to that legislation and not extend to other measures.
But any move to alter the filibuster would intensify Democratic calls to weaken it for other blocked priorities, notably a voting rights measure that Democrats say is needed to offset Republican-led state election laws that impede participation by people of color and others. Conservatives worry that if the anti-filibuster forces win an exemption for the debt legislation, more exceptions are likely to follow.
Mr. McConnell has threatened to bring the Senate to a standstill if Democrats undermine the filibuster. He has said repeatedly that Democrats should instead employ the budget process known as reconciliation to raise the debt limit, which would allow them to take advantage of rules that shield certain fiscal legislation from a filibuster.
Understand the U.S. Debt Ceiling
What is the debt ceiling? The debt ceiling, also called the debt limit, is a cap on the total amount of money that the federal government is authorized to borrow via U.S. Treasury bills and savings bonds to fulfill its financial obligations. Because the U.S. runs budget deficits, it must borrow huge sums of money to pay its bills.
“There is already an existing carveout where Democrats can do it themselves — it’s called reconciliation,” Senator Mitt Romney, Republican of Utah, said on Twitter.
But Democrats have so far refused to embrace the idea of using reconciliation, saying there should be no need to go through that legislative feat when the nation is staring down a fiscal disaster. If Republicans do not want to vote to increase federal borrowing power, the Democrats say, they should simply allow the Democrats to do it on their own.
“Look, the best way to get this done is just for Republicans to get out of the way,” Senator Chuck Schumer, Democrat of New York and the majority leader, said. “None of them have to vote for a debt ceiling; let the 50 Democrats do it.”
Activists have been clamoring all year for Democrats to jettison the filibuster so they can advance the party’s agenda while they retain control of Congress and the White House. They have seized on the debt limit impasse as fresh ammunition.
“Senate Democrats are hurtling toward an easy choice,” said Eli Zupnick, spokesman for the anti-filibuster group Fix Our Senate. “Allow Senator McConnell to crash the economy or finally tackle the outdated and abused Senate filibuster that gives him the power to do so.”
Lawmakers have warned that any change to the filibuster could have far-reaching effects and provoke retaliation by the opposing party.
In 2013, Democrats frustrated by a Republican blockade of President Barack Obama’s judicial nominees changed the rules to allow the nominees to advance on a simple majority vote. Democrats exempted Supreme Court nominees from the change, but in 2017, Republicans moved quickly to expand the new rules, allowing President Donald J. Trump to seat three new Supreme Court justices during his term without the threat of a filibuster.
Some lawmakers also warn that ending the filibuster would allow one party to erase legislation enacted by the other when it assumes power, a prospect that Senator Richard Shelby, Republican of Alabama, called “dangerous for both sides.”