▶ Watch Video: House-approved Capitol attack commission may face partisan battle in Senate

The Senate is expected to vote this week on the House-passed bill creating a commission to investigate the January 6 attack on the U.S. Capitol, despite the threat of a filibuster by Republicans.

Senate Majority Leader Chuck Schumer told reporters Wednesday that the Senate will “likely” vote on the bill this week. The Senate is in recess next week, meaning the vote will be punted to later in June if it does not occur in the coming days.

But most legislation requires 60 votes to advance in the Senate, and Democrats only have a 50-seat majority. Fewer than ten Republicans are expected to support the bill, meaning that it can be filibustered. This will be the first filibuster of the new Congress, a tool that is often used by the minority party to block legislation.

“As far as I’m concerned, that is the kind of issue which should be majority-vote decided. They’re going to use the filibuster on it, and it’s really a sad day,” Senator Dick Durbin, the Democratic whip, told reporters on Wednesday. Durbin and most other Democrats support eliminating the filibuster, which would allow legislation to pass with a majority vote.

The bill would create a 10-member commission evenly divided between members selected by Democratic and Republican leaders. Both sides would have equal subpoena power, and the commission will be tasked with issuing a report with findings about the January 6 attack by the end of the year. Much the language in the legislation is copied from the bill creating the 9/11 commission, which passed with an overwhelmingly bipartisan vote in the Senate in 2002.

Both parties called for a creation of a 9/11-style commission in the aftermath of the riot, when a mob of angry Trump supporters overran the Capitol as Congress was counting the electoral votes. But Republicans have backed down in recent months, arguing that their party should focus instead on retaking Congress the 2022 midterm elections. Senate Minority Leader Mitch McConnell has indicated that he wants to move past January 6, telling reporters on Tuesday that he believed Democrats “would like to continue to debate things that occurred in the past.”

“I think that this is purely political exercise that adds nothing to the subtotal of information,” McConnell said about the legislation. The bipartisan bill, which passed in the Democrat-controlled House earlier this month, was negotiated in part by the Republican ranking member of the House Homeland Security Committee.

Schumer slammed McConnell in a speech on the Senate floor Wednesday, saying that the Republican leader was just “worried the truth could hurt Republicans politically.”

“Look, I am sorry if an independent commission to study an attack on our democracy isn’t a Republican ad maker’s idea of a good time. This is too important,” Schumer said.

Republicans have raised concerns about the structure and scope of the bill, and worried that it could extend beyond its deadline and affect the 2022 midterm elections — despite the requirement in the bill for the commission to wrap up its work by the end of the year. Republican Senator Susan Collins is circulating an amendment to the bill, and is expected to vote to advance the bill so that she can offer it. But even if it is altered the measure is still unlikely to garner support from a sufficient number of Republicans.

Republican Senator Bill Cassidy said that he would be willing to consider the bill if Collins’ amendment pertaining to commission staff selection is accepted. Republicans have worried that the current bill would allow the Democratic commissioners to hire all staffers, and Collins’ amendment would assuage GOP concerns by ensuring Republican commissioners would have an equal hand in staff selection as well.

“If the amendment is accepted, you have one set of potential persuadables, including me. If it’s not accepted, then you have another set, a smaller set of persuadables,” Cassidy told reporters.

GOP Senator Mitt Romney told reporters on Wednesday that he expected two to four Republicans to support the bill.

Romney said McConnell and other Senate Republicans have a “very legitimate point” regarding their concern that the commission is political to make the midterms about Mr. Trump and January 6.

“I have a different point of view, as you know, I think it’s important that some answers, be provided so that we can prevent events like this from occurring again,” Romney said.

With the vote approaching, Republicans are also coming under renewed pressure from Gladys Sicknick, the mother of U.S. Capitol Police Officer Brian Sicknick, who died the day after batting rioters at the Capitol on January 6th. 

Gladys Sicknick has requested a meeting with each Republican senator on Thursday, when she will be at the Capitol, “to discuss the importance of establishing the bipartisan January 6th Commission,” according to a copy of the meeting request obtained by CBS News. 

“Not having a January 6 Commission to look into exactly what occurred is a slap in the faces of all the officers who did their jobs that day. Because of what they did, the people in the building were able to go home that evening and be with their families. Brian and many other officers ended up in the hospital,” she said. “I suggest that all Congressmen and Senators who are against this Bill visit my son’s grave in Arlington National Cemetery and, while there, think about what their hurtful decisions will do to those officers who will be there for them going forward.” 

She also criticized members of Congress who barricaded themselves inside their offices and later claimed rioters walking through the Capitol looked like normal tourists.  

The Washington, D.C. medical examiner’s office said Sicknick died of natural causes the day after the assault, where he was seen being sprayed with a chemical substance by rioters outside the Capitol. In an interview with The Washington Post, chief medical examiner Francisco J. Diaz said Sicknick suffered two strokes at the base of his brainstem caused by a clot in an artery.

Jack Turman contributed to this report.