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.

“I have a feeling we’re coming together for a big win,” Biden said on the eve of the election 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.”

On Tuesday morning, Trump said was optimistic about his chances for victory, predicting big wins in key states such as Florida and Arizona. “We feel very good,” a hoarse-voiced Trump told Fox News in a phone interview.

Trump said he expected victory in all the key states that will decide the election, but said he would not “play games” by declaring his win too early.

What the final polls say about the Trump-Biden race

The president 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.

He has suggested he would deploy lawyers if states are still counting votes after Election Day on Tuesday.

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.

Trump batted away criticism of his handling of the coronavirus pandemic by noting he had recovered from his own infection. “I’m here, right?” he asked his audience, most of whom were packed closely together and not wearing masks, apart from some wearing facial coverings emblazoned with the president’s name.

US election: how Trump and Biden compare on China

Biden has the wind in his sails after indications that Democratic enthusiasm in the early voting may be matching the more visible energy at Trump’s impressive rallies.

In one of US history’s great political gambles, Biden stuck to socially distanced gatherings with small crowds right up to the last moment, in stunning contrast to Trump’s constant, large rallies where few supporters so much as bothered with masks.

But the Democrat, making his third attempt at the presidency, clearly senses that his calmer approach and strict attention to pandemic protocols is what Americans want after four tempestuous years.

“It’s time for Donald Trump to pack his bags and go home,” Biden told supporters in Cleveland.

04:54

The US Electoral College: how does it work and why does it exist?

The US Electoral College: how does it work and why does it exist?

“We’re done with the chaos! We’re done with the tweets, the anger, the hate, the failure, the irresponsibility.”

In chilly downtown Pittsburgh, Justine Wolff said she had cast her ballot for Biden already and was cautiously hopeful he would carry Pennsylvania, which along with Florida may be the tightest of all the swing states that decide close national elections.

“I hope that people have seen the writing on the wall,” said the 35-year-old nurse. “We need some kind of change because this isn’t working for anybody.”

But where many early votes are believed to have been cast by Democrats, Trump’s side is hoping for a massive wave of Republican supporters voting in person on Tuesday.

Lil Wayne joins rappers giving Donald Trump support

The first polling stations opening were in two New Hampshire villages, Dixville Notch and Millsfield, starting at midnight. Most polling stations on the East Coast were to open at 6am or 7am ET.

A tiny hamlet of 12 residents in the middle of the forest, near the Canadian border, Dixville Notch has traditionally voted “first in the nation” since 1960.

The vote took minutes, as did the count: five votes for Biden, and none for Trump.

First lady Melania Trump cast her vote on Tuesday morning at a polling centre in Palm Beach, Florida, close to the president’s Mar-a-Lago resort.

Asked why she did not vote with her husband last week, the first lady told reporters on Tuesday: “It’s Election Day so I wanted to come here to vote today for the election.”

The first lady waved and smiled to reporters. She was the only person not wearing a mask when she entered the Morton and Barbara Mandel Recreation Centre to vote, presumably for Trump. It is unclear if she wore a face covering inside the voting centre.

Trump himself was planning to visit his campaign headquarters in Virginia on Tuesday, while Biden returned to his birthplace of Scranton, the scrappy Pennsylvania town where Trump also visited on Monday.

The former vice-president arrived to a hero’s welcome of more than 100 people cheering across the street. Biden greeted the crowd and said, “It’s good to be home!”

He then signed one of the walls of his childhood home with the message: “From this house to the White House with the grace of God. Joe Biden 11-3-2020.”

Pennsylvania is key to Biden’s White House hopes. He plans to visit Philadelphia later.

Trump vs Biden: armies of lawyers ready if 2020 US election heads to court

There are worries that if the election is close, extended legal chaos and perhaps violent unrest could ensue – not least because Trump has spent months trying to sap public trust in the voting process in a nation already bitterly divided along political fault lines.

Trump has railed for months against mail-in voting and stepped up his aggressive rhetoric on the eve of the election, attacking the Supreme Court and claiming a recent ruling will lead to street violence.

The court recently allowed Pennsylvania to count ballots it receives by mail for up to three days after election day, in line with a decision by local authorities.

01:41

New York shops boarded up ahead of US presidential election day in fear of social unrest

New York shops boarded up ahead of US presidential election day in fear of social unrest

“The Supreme Court decision on voting in Pennsylvania is a VERY dangerous one. It will allow rampant and unchecked cheating and will undermine our entire systems of laws. It will also induce violence in the streets. Something must be done!” Trump said on Twitter.

The social media giant quickly restricted the post, preventing users from retweeting it, while warning: “Some or all of the content shared in this Tweet is disputed and might be misleading about an election or other civic process.”

US election 2020: Donald Trump seeks to undermine vote in final blitz

Facebook slapped a warning on the same message.

There are increasing signs that the election might end up in front of judges, with the Trump campaign indicating it would file suits as quickly as possible. Biden's team has also prepared platoons of lawyers.

In the latest voting rights case, a federal judge ruled that 127,000 ballots cast in Texas in a drive-through system that was set up to help people stay safe during the pandemic will be counted. Local Republican officials had argued the votes were invalid.

Additional reporting by DPA, Reuters and Associated Press