Senate Republicans on Friday halted an effort to form a bipartisan Jan. 6 commission to investigate the Capitol attack, marking the first successful legislative filibuster mounted by the GOP minority. 

The legislation needed 60 votes Friday to overcome a GOP filibuster, but Republicans blocked the legislation from advancing during a procedural vote. The vote was 54 to 35. Just six Republicans joined with Democrats: Sens. Susan Collins of Maine, Lisa Murkowski of Alaska, Mitt Romney of Utah, Bill Cassidy of Louisiana, Ben Sasse of Nebraska and Rob Portman of Ohio.

BRIAN SICKNICK'S MOTHER VISITS CAPITOL TO PUSH FOR JAN. 6 COMMISSION: 'I COULDN'T STAY QUIET ANY MORE'

The House already passed legislation on May 19 to form the independent panel with support from 35 Republicans, despite opposition from former President Trump and House Minority Leader Kevin McCarthy, R-Calif. 

But the legislation faced an uphill climb in the 50-50 split Senate, with Senate Minority Leader Mitch McConnell, R-Ky., also opposing the commission. McConnell argued there are already enough investigations into the Jan. 6 attack. 

Capitol police officers in riot gear push back demonstrators who try to break a door of the U.S. Capitol on Wednesday, Jan. 6, 2021, in Washington. (AP Photo/Jose Luis Magana)

"I do not believe the additional, extraneous ‘commission’ that Democratic leaders want would uncover crucial new facts or promote healing," McConnell said Thursday. "Frankly, I do not believe it is even designed to."

The GOP filibuster Friday on the Jan. 6 commission Friday means the legislation is likely dead for now. But its failure will be sure to intensify pressure on Democrats to abolish the legislative filibuster altogether and just require a simple majority vote to advance future legislation. 

HOUSE APPROVES LEGISLATION TO FORM JAN. 6 BIPARTISAN COMMISSION TO INVESTIGATE CAPITOL RIOT

On Jan. 6, hundreds stormed the Capitol seeking to stop Congress from certifying President-elect Biden's Electoral College win. They violently overtook police officers, destroyed Capitol property and called for the killing of then-Vice President Mike Pence. 

The mob briefly stopped the certification process in Congress as lawmakers had to evacuate the chambers and take cover. In the end, 140 police officers were injured and five people died, including Capitol Police Officer Brian Sicknick, who suffered a stroke after the attack.

More than 400 people have been charged criminally in the Jan. 6 riot. 

Trump supporters try to break through a police barrier, Wednesday, Jan. 6, 2021, at the Capitol in Washington. (AP Photo/Julio Cortez)

Sicknick's mother, Gladys Sicknick, visited GOP senators Thursday to personally urge them to support an independent bipartisan commission to investigate the origins of the attack, saying, "I just couldn't stay quiet anymore."

But politics were strong at play, as Trump still has a big grip on the GOP and Republicans believe moving past the attack is important to their chances of winning the 2022 midterm elections. 

"I want our midterm message to be ... jobs and wages and the economy and national security and safe streets ... and not relitigating the 2020 election," Sen. John Thune, R-S.D., previously told The Hill of concerns on how the commission could undercut the GOP midterm messaging. "Anything that gets us rehashing the 2020 election, I think, is a day lost."

Gladys Sicknick, mother of the late Capitol Police officer Brian Sicknick, arrives at the office of Sen. Ron Johnson, R-Wis., at the Capitol in Washington, Thursday, May 27, 2021. (AP Photo/J. Scott Applewhite)

Prior to the vote, Majority Leader Sen. Chuck Schumer, D-N.Y., implored his GOP colleagues to back the bipartisan panel and to stop supporting Trump's "big lie" that he actually won the 2020 election. 

Afterward, Schumer said Republicans sealed their fate with Trump.

"This vote has made it official: Donald Trump’s big lie has now fully enveloped the Republican Party," Schumer said. "Donald Trump’s big lie is now the defining principle of what was once the party of Lincoln."

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Under the proposal passed by the House, the Jan. 6 panel would be a 10-person bipartisan commission. Half of the commissioners would be appointed by Democrats and the other half would be appointed by Republicans. The commission would have subpoena power to carry out the investigation, but there must be bipartisan agreement on issuing the subpoenas.

The commission would have to issue a final report by Dec. 31, 2021.

House Speaker Nancy Pelosi, D-Calif., slammed the GOP filibuster, especially since Democrats worked across the aisle and agreed "to everything that Republicans asked for" to make the panel bipartisan. She accused Republicans of putting election concerns above the security of Congress and the country.

"Leader McConnell and Senate Republicans’ denial of the truth of the January 6th insurrection brings shame to the Senate," Pelosi said. "Republicans’ cowardice in rejecting the truth of that dark day makes our Capitol and our country less safe."

Fox News' Chad Pergram contributed to this report.