WASHINGTON — With a showdown coming over the creation of an independent commission to investigate the Jan. 6 Capitol assault, Democrats are finally bumping up against the limits of what they can accomplish in the evenly divided Senate without changes to the filibuster rules.
Republicans who see the commission as a threat to their midterm election hopes are poised to employ the procedural weapon to block the formation of the inquiry as early as Thursday, potentially dooming it while underscoring the power of a determined Senate minority to kill legislation even if it is popular and has bipartisan support.
It is the sort of clash that lawmakers have been anticipating since the first day of this Congress, when it was clear that the 50-50 breakdown in the Senate would make it nearly impossible for Democrats to deliver on President Biden’s agenda unless they could do away with the 60-vote threshold for advancing legislation over the objections of any senator.
But rather than court confrontations with Republicans — a strategy that many progressive lawmakers and activists argued was necessary to make the case for scrapping the decades-old practice — Senator Chuck Schumer, Democrat of New York and the majority leader, has skirted the issue. After resorting to a fast-track budget maneuver to muscle through Mr. Biden’s nearly $1.9 trillion stimulus law with a simple majority vote, he has focused on moving a series of bipartisan bills, and allowed time for negotiations between Republicans and Democrats before trying to force action on a host of other issues.
Democrats argue that the grinding approach has been necessary to demonstrate a willingness to work with Republicans, as Mr. Biden pledged he would try to do. They also say it is necessary to prove to centrist Democrats who oppose tinkering with the filibuster that Republicans will never agree to legislation on the scale that Democrats want and the public is demanding, and that changing Senate rules is the only way to achieve the “big, bold” results their party has promised.
But the approach has prompted mounting frustration among some activists who say that Democrats have squandered their opportunity to make the case for ending the filibuster, and with it their chance to push through their most ambitious priorities.
With the Memorial Day holiday looming as an informal deadline for legislative progress, Senate Democrats have made no move to take up a sweeping voting rights bill, new gun safety legislation, expansions of labor and L.G.B.T.Q. rights, a measure to overhaul policing, or legalization for millions of undocumented immigrants, among others.
All of them have passed the Democratic-led House, face stiff Republican opposition in the Senate and were once thought to be prime candidates to elevate the filibuster fight, by highlighting the G.O.P.’s opposition and demonstrating the kinds of initiatives that would die without a change in the rules. Instead, most of the focus has been on the bipartisan infrastructure negotiations and nominations to fill out Mr. Biden’s administration.
“We haven’t had any of those table-setting votes yet,” Brian Fallon, the executive director of the progressive group Demand Justice, said about the idea of drawing out Republicans on the liberal issues. “The more time Republicans buy themselves on infrastructure, the more they are running out the clock.”
Wednesday provided a fresh example of how the quest for bipartisanship can slow things down. The timing of a Senate vote on the Jan. 6 commission remained uncertain as Democrats sought a way to nail down final approval of a measure improving competitiveness with China — legislation with strong backing by members of both parties — even as Republicans sought more debate.
Top Democrats say the filibuster fight will soon come to a head with the debate over creating the independent commission and a commitment by Mr. Schumer to hold a vote on the sweeping voting rights legislation before August. Senator Mitch McConnell of Kentucky, the minority leader, and nearly every other Senate Republican adamantly oppose both, and they seem destined for filibusters that will rekindle the calls to eliminate the tactic.
“We hope to move forward with Republicans,” Mr. Schumer told reporters on Tuesday, “but we’re not going to let them saying no stand in our way.”
Mr. Schumer has been adamant that he will find a way to overcome G.O.P. objections, repeatedly saying that “failure is not an option” on passing legislation to offset new voting rights restrictions being imposed by Republicans in states around the country.
But he has not shown his hand on how he intends to pass that measure or others opposed by Republicans, with at least two Senate Democrats — Joe Manchin III of West Virginia and Kyrsten Sinema of Arizona — insisting that they will not vote to change filibuster rules under any circumstance. On Tuesday, those senators issued a joint statement “imploring” Republicans to find a way to back the bipartisan commission and avoid provoking a filibuster fight that the two Democrats would rather avoid.
Allies of Mr. Schumer said he had little recourse for pressing the filibuster fight until he could unite all 50 Democratic senators behind a piece of legislation, as is the case with the bill creating the bipartisan commission. Most of the other progressive priorities remain shy of the required 50.
Those familiar with the conversations say that Mr. Schumer has been giving Democratic legislative point men on key issues — Senator Richard J. Durbin of Illinois on immigration, Senator Christopher S. Murphy of Connecticut on gun safety and Senator Cory Booker of New Jersey on policing — room to negotiate with potentially receptive Republicans, but that he will not allow those talks to continue indefinitely.
Other Democrats say that while the filibuster fight might not be raging publicly on the floor, it is simmering constantly in the private cloakroom where senators gather, and they know what lies ahead.
“The Republican obstruction is a continuous point of discussion between the senators,” said Senator Jeff Merkley, Democrat of Oregon and a chief author of the expansive voting rights and campaign bill known as S1. “It has been the majority leader’s decision to put bills on the floor that are bipartisan so you don’t see the blockades the way you did in the first months of the Obama administration. We will see them as we go down the road here.”
As for how to enact his measure into law when it faces a filibuster and at least two Democrats who refuse to overrule one, Mr. Merkley said that “it is going to be up to the 50 Democrats to get in a room and figure out how to get it done.”
Democrats tried just that on Wednesday in a private luncheon session to review the voting rights bill. The major development appeared to be that Mr. Manchin, the sole Democrat not backing the measure, attended the discussion after skipping a previous one, but attendees said that no real progress was made and no plan surfaced for pushing the measure over the finish line.
With Mr. Manchin and Ms. Sinema refusing to budge on the issue, Mr. McConnell, an experienced practitioner of the filibuster, believes Republicans have the votes to protect the tactic. He has intensified his criticism of the Democratic agenda and has been increasingly vocal about his determination to block the vast majority of it. That leaves Mr. Schumer and Senate Democrats stuck unless they can determine a way around the filibuster. They are already laying plans to try to advance a huge infrastructure plan through the budget reconciliation process this summer if talks with Republicans break down.
But measures on voting rights, policing, labor protections and other progressive policies are not likely candidates for the budget process. Activists want to see some action on them soon, before what could be a short window of Democratic control of Congress and the White House comes to an end.
“The next two months are going to be absolutely critical,” said Eli Zupnick, a spokesman for the anti-filibuster group Fix Our Senate. “We are going to find out whether Democrats are going to defend the filibuster or take the steps to defend our democracy.”