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More than 100 million Americans voted early in the US presidential election, indicating the highest turnout in more than a century after a fractious and heated race for the White House.
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With queues outside polling stations witnessed across the country, political analysts were watching closely to see if the number of eligible voters casting a ballot would eclipse the 1908 record of 65 per cent.
In 2016, a record 139 million votes were cast, which represented 59.2 per cent of the eligible voting population.
Americans went to the polls despite the number of daily Covid-19 infections hitting highs unseen throughout this year. But they wore face masks and used hand sanitiser to cast their ballots.
The two candidates, Donald Trump, the incumbent, and Joe Biden, the Democratic presidential nominee, spent the day thanking supporters.
Trump predicted a "tremendous" night while visiting his campaign headquarters but also struck a note of caution: "Winning is easy, losing is never easy. Not for me it's not."
Biden visited his childhood home in Scranton, Pennsylvania, and signed his name on the wall with the message: "From this house to the White House with the grace of God."
But for all the positivity of vast numbers of Americans carrying out their simple act of democracy, the country was braced last night for far more turbulent days ahead.
An eight-foot high "unscalable" fence had been erected during Monday night around the White House, similar to the ones put in place during heated anti-racism protests over the summer.
The scene was repeated in city downtowns across the US, with some National Guard units on standby. In Washington DC, police said that demonstrations were expected whatever the outcome.
Trump was due to spend election night at the White House to watch the results come in, knowing opinion polls had him clearly behind Biden in the key swing states.
The US president sounded hoarse during a Fox News phone interview on Tuesday morning, having arrived back in Washington from the last of his five Monday rallies at 2.35am.
On Monday night, Trump tweeted a warning of "violence in the streets" over the Supreme Court decision to let Pennsylvania count postal ballots that arrive before the weekend.
Twitter flagged the tweet, initially hiding it from other users of the social media site and saying "some or all" of the message was "disputed and might be misleading".
In the interview, Trump repeated the core message, however, insisting that he was willing to send in lawyers to fight the case in Pennsylvania, a hotly contested swing state.
Later, during a visit to the Trump campaign headquarters on the outskirts of Washington, the president offered a mixed picture of his hopes for the election night.
He was upbeat about the lines at polling stations – Trump had hoped for a "red wave" of in-person votes after Democrats urged people to vote by mail – and he predicted a "great" night.
Biden, looking to win the White House more than 30 years after he first ran for the presidency, began the day by visiting the graveside of his eldest son, Beau.
Throughout the campaign Biden has said that if his son, who died of cancer in 2015, was still alive it would have been him running for the presidency this year.
Biden spent much of the day in Scranton, his childhood home town. "Thank you, thank you, thank you" he told crowds at one point, talking into a loudspeaker through a face mask.
The Democratic presidential candidate was due to be in his current home town of Wilmington, Delaware – a state he has represented for 36 years as a senator – for results night.
The unprecedented wave in early voting partly reflects public health concerns over the Covid-19 pandemic.
Officials in most states made it easier to vote by changing the rules once the outbreak struck.
Many voters opted to avoid the queues which were always likely on election day either by voting by post or, in some states where it was permitted, making use of early in-person voting.
In four states – Washington, Montana, Texas and Hawaii – more people had voted before Tuesday than the total who voted in the whole of the 2016 election.
Which candidate was best placed to handle the Covid-19 pandemic was the dominant issue in the election campaign ever since the outbreak hit America in the spring. Biden put the focus on ensuring restrictions that would help limit the spread of coronavirus would be kept in place, while Trump stressed the need to keep the economy growing.
In recent weeks the daily Covid-19 case count in the US has approached 100,000, well above its peak of around 75,000 during the virus's second wave over the summer.
The Biden campaign said their candidate was planning to give a speech at some point on results night at a Delaware convention centre, depending on how the results emerged.
Trump had reportedly invited 400 people to attend an election night party in the White House, the residence he hoped to be holding on to after the gruelling election campaign.
The FBI said on Tuesday night said it was investigating "robocalls" – pre-recorded phone messages that use a computerised autodialer to make multiple unsolicited calls – that urged people to "stay home".
It was estimated that tens of thousands of people may have received one of the calls, in which a voice says: "Hello. This is just a test call. Time to stay home. Stay safe and stay home."
A video of the event surfaced online, prompting a police investigation.