The president, who has been focused on drawing an economic contrast between Democrats and the Republican Party, shined a spotlight on “ultra MAGA” Republicans – a reference to Trump’s “Make America Great Again” slogan – calling them a minority but “driving force” of the Republican Party.

“There’s an alarming rise in the number of people in this country condoning political violence or simply remaining silent,” Biden added. “In our bones we know Democracy is at risk, but we also know this: it’s in our power to preserve our democracy.”

He called out the hundreds of candidates who have denied the 2020 election result and refused to commit to accepting the results of the coming midterms.

“This driving force is trying to succeed where they failed in 2020 to suppress the rights of voters and subvert the electoral system itself,” Biden said. “That is the path to chaos in America. It’s unprecedented. It’s unlawful. And it is un-American.”

Pointing to mounting concerns over political violence as well as threats of America’s long tradition of hard-fought but peaceful and accurate elections, he said these Republicans are “trying to succeed where they failed in 2020 to suppress the rights of voters and subvert the electoral system itself”.

The speech came days after a man seeking to kidnap House Speaker Pelosi severely injured her husband, Paul Pelosi, in their San Francisco home in the worst recent example of political violence that burst forth with the January 6 insurrection and has continued with alarming, though less-spectacular incidents.

Election workers nationwide have questioned whether to go back to work following increased intimidation and harassment ahead of the Election Day. At least five people have been charged with federal crimes for harassing workers as early voting has got under way.

Reports of people watching ballot boxes in Arizona, sometimes armed or wearing ballistic vests, have raised serious concerns about voter intimidation. Election officials nationwide are bracing for confrontations at polling sites led by a flood of conspiracy theorists who have signed up to work as partisan poll watchers.

Emphasising that it is the first federal election since the January 6, 2021, insurrection and Trump’s attempts to overturn the will of voters in the 2020 presidential election, Biden called on voters to reject candidates who have denied the results of the vote – which even Trump’s administration declared to be free of any widespread fraud or interference.

Biden asked voters to “think long and hard about the moment we are in”.

“In a typical year, we are not often faced with the question of whether the vote we cast will preserve democracy or put it at risk,” he said. “But we are this year.”

Biden also aimed to get ahead of conspiracy theories about the ongoing vote, saying Americans were voting early, by mail and by postal vote and it would take time to tally them “in a legal and orderly manner”.

Major changes in voting in 2020 because of the pandemic prompted more early voting and mail-in voting and saw record turnout. It took five days before the results of the 2020 presidential election were final.

“It is important for citizens to be patient,” Biden said.

Biden delivered his remarks from Washington’s Union Station, blocks from the US Capitol, the White House said, just six days before polls close on November 8 and as more than 27 million Americans have already cast their ballots.

“It’s from Capitol Hill, because that is where there was an attempt to subvert our democracy,” said White House senior adviser Anita Dunn told Axios, referencing to the January 6 attack.

Before Biden’s speech US Capitol Police Chief Tom Manger said he’s reviewed the attack on Pelosi’s husband and believes today’s political climate calls for more resources and better security for members of Congress after a massive increase in threats to lawmakers following January 6.

He also made a rare call to stop the rancorous conspiracy talk that has swirled around the attack.

“Our brave men and women are working around the clock to meet this urgent mission during this divisive time,” he said in a statement. “In the meantime, a significant change that will have an immediate impact will be for people across our country to lower the temperature on political rhetoric before it’s too late.”

Biden last delivered a prime-time speech on what he called the “continued battle for the soul of the nation” on September 1 outside Independence Hall in Philadelphia, in which he condemned the “MAGA forces” of Trump and his adherents as a threat to America’s system of government.

The new remarks come as hundreds of candidates who have falsely denied the legitimacy of the 2020 presidential election are on ballots across the country, with many poised to be elected to critical roles overseeing elections.

In contrast to the September remarks, which drew criticism from some corners for being paid for by taxpayers, Biden’s Wednesday night speech was hosted by the Democratic National Committee.

Many Americans remain pessimistic about the state of US democracy. An October poll by the Associated Press-NORC Centre for Public Affairs Research found that just 9 per cent of adults think democracy is working “extremely” or “very well,” while 52 per cent say it’s not working well.

Additional reporting by Bloomberg