Voting legislation that Democrats and civil rights leaders say is vital to protecting US democracy collapsed late on Wednesday when two senators refused to join their own party in changing Senate rules to overcome a Republican filibuster after a raw, emotional debate.
The outcome was a stinging defeat for President Joe Biden and his party, coming at the tumultuous close to his first year in office.
“I am profoundly disappointed,” Mr Biden said in a statement after the vote.
However, the president said he is “not deterred” and vowed to “explore every measure and use every tool at our disposal to stand up for democracy".
In back-to-back votes, Senate Republicans first blocked Democrats' move to advance the voting rights legislation towards passage. It was the fifth time in less than a year that they did so.
They employed the decades-old filibuster rule to stop the legislation, which requires the co-operation of at least 60 of the Senate's 100 members to keep bills alive. The Senate currently is split 50-50.
In lightning speed, Senate Majority Leader Chuck Schumer, a Democrat, then moved to revamp the filibuster rule by lowering the 60-vote threshold to 50. This time, it was not Republicans, but Mr Schumer's own Democrats — conservatives Joe Manchin and Kyrsten Sinema — who put the final nail in the coffin by voting against the rules change.
Senate Republican Leader Mitch McConnell warned against changes to the rule.
“Factional fires are burning hot all across our country,” Mr McConnell said, adding altering the filibuster rule “would shatter the Senate for short-term power.”
Now, with the 2022 midterm elections heating up that will see the election of all 435 House of Representatives members and one third of the Senate, the partisan fighting is only expected to deepen.
The voting rights bill that was passed by the US House but buried on Wednesday by the Senate would have established minimum federal voting standards so that any registered voter could request a mail-in ballot.
It also would have established at least two weeks of early voting and expanded use of ballot drop boxes that make voting more convenient in many areas.
The Democrats' legislation also would have attempted to remove partisanship from the way congressional districts are redrawn every decade.
Democrats argued their bill would strengthen a democracy buffeted by domestic strife and the January 6, 2021, violent riot at the US Capitol at the hands of thousands of supporters of then-president Donald Trump.
Underscoring deep divisions in Congress and throughout the nation, Republicans countered that Democrats had fabricated a crisis over voting rights and maintained that little or nothing needed to be done with the way states administer elections.
The final tally on limiting debate on the election reform bill was 49-51. No Republicans voted to advance it.
Then, all 50 Republicans plus Mr Manchin and Ms Sinema defeated the move to change the filibuster rule on a one-time basis by a vote of 52-48.
As the drama was playing out in the Senate, Mr Biden told a news conference on Wednesday that he had not given up hope of advancing voting rights.
“We've not run out of options yet,” the Democratic president said.
Agencies contributed to this report