Democrat Sens. Joe Manchin and Kyrsten Sinema bucked President Biden and Majority Leader Chuck Schumer Wednesday by voting against an effort to change the Senate's filibuster threshold from 60 votes to 51. 

Schumer, D-N.Y., forced a vote on whether to change the filibuster threshold after Republicans used it to block Democrat-backed election bills. Both Sinema, D-Ariz., and Manchin, D-W.Va., supported the election legislation. But they said using a party-line vote to change the longtime Senate filibuster procedure was a step too far, and contributed to blocking the move in a 52-48 vote. 

"Allowing one party to exert complete control in the Senate with only a simple majority will only pour fuel on the fire of political whiplash and dysfunction that is tearing this nation apart," Manchin, D-W.Va., said. "Contrary to what some have said, protecting the role of the minority – Democrat or Republican – has protected us from the volatile political swings that we have endured over the last 233 years." 

Sen. Joe Manchin talks to the press about debt

Sen. Joe Manchin, D-W.Va., a key holdout vote on President Joe Biden's domestic agenda, makes a statement to reporters about Republicans and Democrats resolving their fight over raising the debt limit, at the Capitol in Washington, Wednesday, Oct. 6, 2021. (AP Photo/J. Scott Applewhite) (AP Photo/J. Scott Applewhite)

VULNERABLE SENATE DEM KELLY SAYS HE'LL VOTE TO NUKE FILIBUSTER, LEAVING MANCHIN AND SINEMA EVEN MORE ISOLATED

Sinema made her case for why the Senate should keep the filibuster last week, arguing that in an equally divided Senate, "our mandate, it seems evident to me, [is] work together and get stuff done for America."

Wednesday's vote was the culmination of years of pressure from progressive activists for Democrats to ditch the filibuster if they took power in 2020 and comes less than five years after 26 sitting Democratic senators signed a 2017 letter supporting the filibuster. 

The filibuster proposal Schumer put forward would have only applied to the two bills the Senate was considering Thursday. Schumer called it a "modest one time change of Senate rules to establish a talking filibuster for this voting rights legislation." But Manchin and Sinema still voted against it.

More and more Senate Democrats came out in favor of filibuster changes during 2021, as President Biden and party activists lamented that Senate Republicans were blocking much of the Democrats' agenda. Sen. Mark Kelly, D-Ariz., was the latest Democrat to announce he favors filibuster changes. He said Senate gridlock was a major factor in his decision. 

Senator Kyrsten Sinema, D-Ariz., listens during a news conference in the Dirksen Senate Office Building in Washington, D.C., on Wednesday, July 28, 2021 (Stefani Reynolds/Bloomberg via Getty Images)

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"My year in the Senate has shown me how dysfunctional this place can be and how that prevents progress on issues that matter to Arizonans," Kelly, D-Ariz., who faces a difficult reelection this year, said. "If campaign finance and voting rights reforms are blocked again this week, I will support the proposed changes to pass them with a majority vote." 

But in the 50-50 Senate, Schumer needed all Democrats to support his filibuster gambit for it to pass it – and Sinema and Manchin remained steadfast in their opposition to any changes, to the relief of Republicans. 

"Fortunately there are two members of the Democratic Conference who believe in the institution and understand that in the very near future the shoe might be on the other foot and are prepared to prevent this disruptive move," Senate Minority Leader Mitch McConnell, R-Ky., said. "I congratulate both of them for their courage."