WASHINGTON (NewsNation Now) — Legislation creating a 9/11-style commission to investigate the deadly Jan. 6 riots at the U.S. Capitol will take center stage in the House of Representatives this week as Democrats seek quick passage.

Trump supporters stormed the building following a speech in which the then-president repeated unfounded claims that his November 2020 election defeat was the result of widespread voter fraud. Five people including a Capitol Police officer died in the violence.

Democrats say a bipartisan commission investigating the attack, including what led to it, is more important than ever after some Republicans disputed the severity of the insurrection.

“This was an armed assault on our democracy, and I’m a witness — I’m a victim and a witness to it,” says New Hampshire Rep. Annie Kuster. She received treatment for post-traumatic stress after she was also trapped in the House gallery that day and heard rioters trying to break through the doors close to where she was hiding.

During a House hearing last week, Republican Representative Andrew Clyde said it would be “a bold-faced lie” to label the events of Jan. 6 an “insurrection.” Instead, he likened the events of that day to “a normal tourist visit.”

Trump, who was impeached afterward by the Democratic-led House on a charge of inciting insurrection, continues to claim the election was marred by fraud, and House Republicans last week ousted Representative Liz Cheney from their leadership for rejecting Trump’s unfounded claims.

The bill to be considered on Tuesday by the House Rules Committee establishes a bipartisan commission of 10 prominent citizens to investigate the causes of the attack, security shortcomings and intelligence information leading up to Jan. 6.

The panel would have to release a final report by Dec. 31, before Congress’ next election season kicks up in earnest.

Trump’s activities are likely to become a focal point, as the legislation explicitly charges the commission with looking into “the influencing factors that fomented such attack.”

A vote on the bill by the full House is expected later this week. The probe is likely to focus on intelligence failures ahead of the attack and why it took hours for National Guard troops to reinforce the overwhelmed Capitol Police.

House Republican Leader Kevin McCarthy said Tuesday he would oppose the commission, calling it “duplicative and potentially counterproductive.”

McCarthy said that given the “shortsighted scope that does not examine interrelated forms of political violence in America, I cannot support this legislation.” He pushed to have the new commission also investigate other groups, beyond the violent uprising by supporters trying to stop the certification of President Joe Biden’s election. 

McCarthy’s opposition all but ensures this week’s vote will have less Republican support in the House, and dims its chances in the evenly divided Senate — threatening the bipartisan commission’s chances

House Speaker Nancy Pelosi said that protecting the Capitol and the people who work inside it is of “the highest priority,” and that a commission is imperative “to examine and report upon the facts, causes and security relating to the terrorist mob attack.”

More than 400 people have been arrested for taking part in the violence, which also injured dozens of law enforcement officers.

Under the bill, Democrats and Republicans would have equal say over selecting commissioners and both sides would have to approve witness subpoenas.

Lawmakers say they have boosted security measures to protect themselves and their families, money for which will be part of a broad $1.9 billion spending bill that the House will vote on this week, along with a separate measure that would create a bipartisan commission to investigate the Jan. 6 attack. Democrats, in particular, say both bills are crucial to try to reconcile the trauma that many still feel.

The security spending bill would provide congressional offices with more money to combat those threats, including enhanced travel security, upgrades to home-district offices and better intelligence to track people down. The bill would also “harden” the complex by reinforcing doors and windows, adding security vestibules and cameras and providing dollars for removable fencing that could quickly be erected during a threatening situation while leaving the Capitol open to visitors.

Many Republicans in Congress have demanded the commission also investigate last summer’s largely peaceful protests against racism and police violence, including the Black Lives Matter movement, that were sparked by George Floyd’s murder in Minneapolis, an event unrelated to the insurrection at the Capitol.