Activists say they have planned hundreds of protests to take place in cities across the US on 4 November should president Donald Trump refuse to accept the result of November’s election.
Earlier in the campaign, Mr Trump repeatedly obfuscated when asked by reporters whether he would hand over the keys to the White House in the event he loses to Joe Biden.
Following pressure from a raft of top GOP figures, retired and current generals, Mr Trump appeared to row back on that position at last week's second presidential debate when he said he would commit to a peaceful transfer of power.
However, the president, 74, refused to rule out contesting the result of November's poll, as he again trotted out unsubstantiated claims that the election could fall foul to voter fraud, as millions of Americans cast their ballots via post due to the ongoing coronavirus pandemic.
Sean Eldridge, a former Democratic candidate for Congress and key organiser at Stand Up America - a New York-based anti-Trump organisation - says Democracy activists across the country are planning mass demonstrations to protest against the president if he refuses to accept defeat against Mr Biden, 77.
"We're preparing for the worst," Mr Eldridge, 34, told AFP. “This is pretty unprecedented in American politics to have to be worried about whether a sitting president will accept the election results and ensure a peaceful transition of power".
Increasing numbers of mail-in ballots mean the winner of this year's race for the Oval Office may not be announced until after election night, with Federal Elections Commission chief Ellen Weintraub warning in August that Americans will need to "take a deep breath and be patient this year".
If the result of the election is close, then Mr Trump is expected to contest the outcome in the courts and could take the issue all the way to the supreme court, which will have a solidly right-leaning balance of power once judge Amy Coney Barrett is confirmed by the Senate.
This could result in a standoff between the two candidates that could last weeks if not months.
Mr Eldridge, who was also involved in America's successful movement to legalise gay marriage, is part of the Protect the Results coalition, which has put in place plans to hold 250 rallies from all over the country. They represent millions of Americans, according to Eldridge.
“We need to make sure that any corrupt pressure from Trump to undermine the election results will be met by a swift response from the American people to demand that every vote be counted and demand that the final valid results be respected," Mr Eldridge told AFP.
“I hope we will not have to mobilise...[we] are not going to be intimidated by the dangerous rhetoric and the violence we are seeing on the other side," he added.