Fulfilling a commitment after a failed effort to launch a congressional probe into the deadly Jan. 6 Capitol riot, House Speaker Nancy Pelosi announced Thursday a House select committee will investigate the attacks.

Pelosi, according to reports, called Jan. 6 “one of the darkest days in our nation’s history” and said the select committee will probe “the facts and causes of the attack” and deliver recommendations.

In late May, the U.S. Senate blocked an effort to establish a probe into the Jan. 6 riot, marking the first successful legislative filibuster this session. By a 54-35 vote, the Senate blocked an effort to open debate on the bill.

“Democrats worked across the aisle, agreeing to everything that Republicans asked for,” Pelosi said after the vote. “We did this in the interest of achieving a bipartisan commission. In not taking yes for an answer, Republicans clearly put their election concerns above the security of the Congress and country.”

In a letter to other senators, Majority Leader Chuck Schumer said “Senate Republicans, at the personal request of Leader [Mitch] McConnell, also continue their brazen attempts to whitewash the attack of January 6th by filibustering the House-passed bipartisan January 6th Commission, even though Speaker Pelosi and I agreed to changes proposed by Senator [Susan] Collins.”

Broad Republican opposition was expected, even as the family of a Capitol Police officer who collapsed and died after the siege and other officers who battled rioters went office to office asking GOP senators to support the commission. The insurrection was the worst attack on the Capitol in 200 years and interrupted the certification of Democrat Joe Biden’s win over Donald Trump.

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

Though the Jan. 6 commission bill passed the House earlier this month with the support of almost three dozen Republicans, GOP senators said they believe the commission would eventually be used against them politically. And Trump, who still has a firm hold on the party, has called it a “Democrat trap.”

While initially saying he was open to the idea of the commission, which would be modeled after an investigation of the 9/11 terrorist attacks, McConnell turned firmly against it. He has said he believes the panel’s investigation would be partisan despite the even split among party members.

McConnell, who once 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.”

The Republican opposition to the bipartisan panel has revived Democratic pressure to do away with the filibuster, a time-honored Senate tradition that requires a vote by 60 of the 100 senators to cut off debate and advance a bill. With the Senate evenly split 50-50, Democrats need support of 10 Republicans to move to the commission bill, sparking fresh debate over whether the time has come to change the rules and lower the threshold to 51 votes to take up legislation.

The Republicans’ political arguments over the violent siege — which is still raw for many in the Capitol, almost five months later — have frustrated not only Democrats but also those who fought off the rioters.