Senate Republicans are poised to block the creation of a special commission to examine the deadly Jan. 6 attack on the Capitol, dashing hopes for a bipartisan panel amid a GOP push to place the violent insurrection from Donald Trump’s supporters behind them.

Broad Republican opposition was expected in what is the first powerful Senate filibuster of this Biden presidency, even as the household of a Capitol Police officer who collapsed and died after the siege and other officers that fought rioters went office to office requesting GOP senators to support the commission. The insurrection was the worst assault on the Capitol in 200 decades and interrupted the certificate of Democrat Joe Biden’s triumph over Trump.

A vote on the procedural motion was bumped to Friday after delays on an unrelated bill to boost scientific research and growth pushed back the schedule.

The expected vote is emblematic of the profound mistrust between the two parties because the siege, which includes sowed deeper divisions on Capitol Hill although lawmakers from the 2 parties fled together by the rioters that day. The events of Jan. 6 have become an increasingly fraught topic among Republicans as some from the party have downplayed the violence and defended that the rioters who affirmed Trump and his false insistence that the election has been stolen from him.

While initially saying he had been open to the notion of this commission, which would be modeled after an investigation of those 9/11 terrorist strikes, Senate Republican leader Mitch McConnell turned firmly against it in recent days. He’s said he thinks the panel’s investigation would be partisan despite the split among party members.

McConnell, who said Trump was responsible for”provoking” the mob attack on the Capitol, said of Democrats,”They’d like to continue to litigate the former president, into the future.”

Still, a handful of Republicans — if not enough to save it — were expected to vote to move forward with the bill. Alaska Sen. Lisa Murkowski has said she will support the legislation because she needs to find out more about what happened that day and why.

“Truth is hard things, but we have got a duty to it,” she told reporters Thursday evening. “We simply can’t pretend that nothing terrible happened, or that people simply got too excitable. Something bad happened. And it’s important to put that out.”

Of her colleagues opposing the commission, Murkowski said a few are concerned that”we do not wish to rock the boat.”

With the Senate evenly split 50-50, Democrats require support of 10 Republicans to move to the commission invoice, sparking fresh debate over whether the time has come to change the rules and lower the threshold 51 votes to take up laws.

The Republicans’ political debates within the abusive siege — that remains raw for many in the Capitol, nearly five months after — have frustrated not only Democrats but also those who fought the rioters.

Michael Fanone, a Metropolitan Police Department officer who responded to the assault, stated between meetings with Republican senators that a commission is”necessary for all of us to heal as a country from the trauma that all of us experienced that day.” Fanone has clarified being hauled down the Capitol steps by rioters who stunned him with a stun gun and beat him.

Sandra Garza, the girlfriend of Capitol Police Officer Brian Sicknick, who collapsed and died after battling the rioters, said of the Republican senators,”You know they are here now and with their families and comfortable due to the actions of law enforcement daily.”

“So I don’t know why they’d resist getting into the bottom of what happened that day and completely understanding how to prevent it.

Video of this rioting shows two men spraying Sicknick and a second officer using a compound, but the Washington medical examiner said he suffered a stroke and died from natural causes.

In a statement Wednesday, Mrs. Sicknick suggested the competitions of the commission”see my son’s grave in Arlington National Cemetery and, while there, think about what their hurtful decisions will do to those officers that will be there for them moving forward.”

Dozens of different police officers were injured as the rioters pushed beyond them, breaking through windows and doors and searching for lawmakers. The protesters constructed a mock gallows in front of the Capitol and called for the hanging of Vice President Mike Pence, who had been overseeing the certification of the presidential vote. Four protesters died, including a woman who had been shot and killed by police as she tried to break in the House room with lawmakers still indoors.

“We’ve got a mob overtake the Capitol, and we all can’t convince the Republicans to join us in creating historic record of the event? “That tells you what is wrong with the Senate and what is wrong with the filibuster.”

Most Democrats are warning that if Republicans are prepared to use the filibuster to stop an arguably popular step, it shows the limits of trying to broker compromises, particularly on bills related to election reforms or other facets of the Democrats’ agenda.

For now, though, Democrats don’t have the votes to modify the rule. West Virginia Sen. Joe Manchin and Arizona Sen. Kyrsten Sinema, equally medium Democrats, have said they want to maintain the filibuster.

Biden, asked concerning the commission at a stop in Cleveland, said Thursday,”I can’t imagine anyone voting against” it.

Republican Texas Sen. John Cornyn, who once supported the idea of this commission, said he now believes Democrats are trying to use it as a political instrument.

“I don’t believe this is the only means to get to the bottom of what occurred,” Cornyn said, noting that Senate committees will also be taking a look at the siege.