Trump’s secret weapon for election victory
The majority of polls show Mr Biden is leading Mr Trump, but the polls were infamously wrong in 2016 and Mr Trump was elected president.
Mr Trump's supporters are fired up, but are they also shy? Multiple US media outlets are reporting on the so-called shy Trump voters.
These are voters who love Trump and his policies but are reluctant to tell pollsters who they're voting for.
This could mean the polls are misleading and the huge Biden lead is merely a mirage.
For example, The Trafalgar Group believes Mr Trump's support is under-represented in majority of polls.
Trafalgar's Robert Cahaly said there was a hidden Trump vote that was not being accounted for in most polls.
"There are more (shy Trump voters) than last time and it's not even a contest," Mr Cahaly said.
"We live in a country where people will lie to their accountant, they'll lie to their doctor, they'll lie to their priest, and we're supposed to believe they shed all of that when they get on the telephone with a stranger?" he told Politico.
He added it was "quite possible" that the polling industry was headed for another embarrassing failure like in 2016.
Jon McHenry, a Republican pollster with North Star Opinion Research, said he did not think there were many "shy" Trump supporters who would lie about their intentions.
He said a "skewed response rate pattern" meant Trump voters were less likely to respond to polls.
"I can't definitively say there is no response bias, but I'm sceptical of it, and it certainly wouldn't be enough to explain the national deficits we're seeing," he said.
The Washington Post is also sceptical that the "shy" Trump voter phenomenon exists.
"The more likely explanation is that pollsters under-represented non-college educated voters in 2016 - which meant most of the political class failed to notice the magnitude of Trump's surge," Michael Bocian wrote, who works for Democratic polling firm GBAO.
Planet America host Chas Licciardello discussed the shy Trump voter phenomenon during a special edition of ABC's The Drum on Tuesday and said the polling methods in America appeared to have improved since 2016.
"First of all the states that were the biggest miss … Wisconsin, Michigan and Pennsylvania, especially in Wisconsin, they didn't poll nearly as much as they are now."
He also said there was no evidence for the shy Trumpers theory.
"We've heard recently about shy Trumpers. That isn't proven," he said.
What has been proven is that people without a university education do not respond to polls as much.
"It just so happens that Trump appealed very much in 2016 to non-college-educated people so they were underrepresented in polls," Licciardello said.
"These days most respected pollsters do weight education."
VOTERS TURN OUT IN DROVES
A record-breaking number of early votes - more than 100 million - have already been cast in an election that has the bitterly divided country on edge and is being closely watched around the world.
The first polls close in several eastern states at 10am (0000 GMT) but the winner may not be known on election night - or possibly even for days - because of the huge number of mail-in ballots that need to be counted.
The 74-year-old Trump, who has repeatedly sought to cast doubt on the legitimacy of mail-in ballots and the counting of votes beyond Election Day, said voters had a right to a timely result.
"The whole world is waiting," he said during a visit to Republican National Committee offices in Arlington, Virginia.
"You can't have these things delayed for many days," Mr Trump said, adding ominously that "a lot of bad things" can happen.
"We should be entitled to know who won on November 3," he said.
Originally published as Trump's secret weapon for election victory