Americans began casting ballots on Tuesday in an Election Day unlike any other, braving the threat of Covid-19 and the potential for violence and intimidation after one of the most polarising presidential races in US history.

In and around polling places across the country, reminders of a 2020 election year shaped by the pandemic, civil unrest and bruising political partisanship greeted voters, although more than 90 million ballots have been already submitted in an unprecedented wave of early voting.

Many wore masks to the polls either by choice or by official mandate with the coronavirus outbreak raging in many parts of the country.

After a summer of nationwide protests against police violence and racism, businesses in several major US cities were again boarded up as a precaution against unrest, an extraordinary sight on Election Day in the United States.

The American Civil Liberties Union and other civil rights groups said they were watching closely for signs of voter intimidation, and the US Justice Department’s Civil Rights Division said it would deploy staff to 18 states.

Democratic presidential candidate Joe Biden asked Americans to trust him as they had in 2008 and 2012 alongside Barack Obama. “We can heal the soul of this nation — I promise we won’t let you down,” he tweeted.

Voters in Dixville Notch, a village of 12 residents in the US state of New Hampshire, kicked off Election Day at the stroke of midnight on Tuesday by voting unanimously for Biden.

The vote and count only took a few minutes, with five votes for Biden and none for President Donald Trump.

Polls began opening on the East Coast on Tuesday as election officials warned that millions of absentee ballots could slow the tallies, perhaps for days, in some key battleground states and as Trump threatened legal action to prevent ballots from being counted after Election Day.

Those yet to vote headed to polling places on Tuesday despite another spike in Covid-19 cases that has hit much of the country. Among those braving the polls were voters who may have wanted to vote by mail but waited too long to request a ballot or those who didn’t receive their ballots in time.

Election officials across some 10,000 voting jurisdictions scrambled to purchase personal-protective equipment, find larger polling places, replace veteran poll workers who opted to sit out this year’s election due to health concerns and add temporary workers to deal with the avalanche of mail ballots.

Biden leading in polls

More than 99 million Americans have cast their ballots in early voting, according to the US Elections Project.

The United States is more divided and angry than at any time since the Vietnam War era of the 1970s — and fears that Trump could dispute the result of the election are only fueling those tensions.

Despite an often startlingly laid-back campaign, Biden, 77, leads in almost every opinion poll, buoyed by his consistent message that America needs to restore its “soul” and get new leadership in the midst of a coronavirus pandemic that has killed more than 231,000 people.

Hours before the polling was to begin, Biden tweeted that he would “govern as an American president”.

“I will work with Democrats and Republicans, and I’ll work as hard for those who don’t support me as for those who do.”

“I have a feeling we’re coming together for a big win tomorrow,” Biden said in Pittsburgh, Pennsylvania, a vital electoral battleground where he was joined by pop superstar Lady Gaga.

“It’s time to stand up and take back our democracy.”

But Trump was characteristically defiant to the end, campaigning at a frenetic pace with crowded rallies in four states on Monday, and repeating his dark, unprecedented claims for a US president that the polls risk being rigged against him.

After almost non-stop speeches in a final three-day sprint, he ended up in the early hours of Tuesday in Grand Rapids, Michigan — the same place where he concluded his epic against-the-odds campaign in 2016 where he defeated apparent front-runner Hillary Clinton.

Despite the bad poll numbers, the 74-year-old Republican real estate tycoon counted on pulling off another upset.

“We’re going to have another beautiful victory tomorrow,” he told the Michigan crowd, which chanted back: “We love you, we love you!”

“We’re going to make history once again,” he said.