A confident Joe Biden says the Democrats remain on track to claim the White House, telling America: "We believe we will be the winners."
Biden has just spoken to the nation and said: "After a long night of counting it's clear we're winning enough states to win 270 votes to win the presidency."
He and deputy Kamala Harris were on track to win more votes than any other ticket in history.
Earlier today Biden took another step towards the White House, with pundits predicting he will win the key state of Wisconsin - and with it 10 crucial electoral votes.
Meanwhile, President Donald Trump has stepped up legal threats over several remaining states - with lawyers heading to court to halt the vote counting in Michigan. They claim they have been denied "meaningful access" to observe the counting in the state, which contributes 16 votes to the Electoral College.
His campaign team is also seeking to stop the ballot counting in Pennsylvania - even though they are claiming victory in the state with 84 per cent of votes tallied.
The latest results have Biden with 248 votes compared to Trump's 214. The winner requires 270 votes.
Trump has already indicated he will demand a recount in Wisconsin - even before the final result is known. Another challenge is expected in Michigan.
The threats indicate there could be a string of legal challenges and recount requests that will drag out the final result.
The fate of the United States presidency is precariously balanced as Trump and Biden battle for three familiar battleground states — Wisconsin, Michigan and Pennsylvania — that could prove crucial in determining who wins the White House.
It is unclear when or how quickly a winner might be determined. A late burst of votes in Michigan and Wisconsin has given Biden a small lead in those states, but it is still too early to call the race. Hundreds of thousands of votes are also outstanding in Pennsylvania.
Biden revealed today that he was already fundraising to set up "the largest election protection effort ever assembled".
"Because Donald Trump doesn't get to decide the outcome of this election — the American people do," he said in a tweet.
The margins in the remaining states are exceedingly tight, with the candidates trading wins in battleground states. Trump picked up Florida, the largest of the swing states, while Biden flipped Arizona, a state that has reliably voted Republican in recent elections. Neither cleared the 270 Electoral College votes needed to carry the White House.
Just seven states remain up for grabs – Alaska, Georgia, Nevada, North Carolina, Michigan, Pennsylvania and Wisconsin. But experts say the votes from the last three could take particularly long to tally up - meaning we could be in for a frustrating wait.
Drama erupted late in the night (US time). In an extraordinary move from the White House, Trump falsely claimed victory, saying the result would be taken to the US Supreme Court and declaring the vote "a fraud". It was unclear exactly what legal action he might try to pursue.
Biden, briefly appearing in front of supporters in Delaware, urged patience, saying the election "ain't over until every vote is counted, every ballot is counted".
"It's not my place or Donald Trump's place to declare who's won this election," Biden said. "That's the decision of the American people."
Vote tabulations routinely continue beyond Election Day, and states largely set the rules for when the count has to end. In presidential elections, a key point is the date in December when presidential electors met. That's set by federal law.
Several states allow mailed-in votes to be accepted after Election Day, as long as they were postmarked by Tuesday. That includes Pennsylvania, where ballots postmarked by November 3 can be accepted if they arrive up to three days after the election.
Pennsylvania Governor Tom Wolf tweeted that his state had more than one million ballots to be counted and that he "promised Pennsylvanians that we would count every vote and that's what we're going to do".
Trump appeared to suggest those ballots should not be counted, and that he would fight for that outcome at the high court. But legal experts were dubious of Trump's declaration.
"I do not see a way that he could go directly to the Supreme Court to stop the counting of votes. There could be fights in specific states, and some of those could end up at the Supreme Court. But this is not the way things work," said Rick Hasen, a professor of law and political science at the University of California-Irvine.
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Trump has appointed three of the high court's nine justices including, most recently, Amy Coney Barrett.
Democrats typically outperform Republicans in mail voting, while the GOP looks to make up ground in Election Day turnout. That means the early margins between the candidates could be influenced by which type of votes — early or Election Day — were being reported by the states.
Throughout the campaign, Trump cast doubt about the integrity of the election and repeatedly suggested that mail-in ballots should not be counted. Both campaigns had teams of lawyers at the ready to move into battleground states if there were legal challenges.
The following is a list of the states won by each candidate and the corresponding number of electoral votes, based on the projections of US media including CNN, Fox News, MSNBC/NBC News, ABC, CBS and The New York Times. In the case of Arizona, AFP used the projection made by the Associated Press.
BIDEN: (238) Arizona (11) California (55) Colorado (9) Connecticut (7) Delaware (3) District of Columbia (3) Hawaii (4) Illinois (20) Maine (3)** Maryland (10) Massachusetts (11) Minnesota (10) Nebraska (1)* New Hampshire (4) New Jersey (14) New Mexico (5) New York (29) Oregon (7) Rhode Island (4) Vermont (3) Virginia (13) Washington (12)
The tight overall contest reflected a deeply polarised nation struggling to respond to the worst health crisis in more than a century, with millions of lost jobs, and a reckoning on racial injustice.
Trump kept several states, including Texas, Iowa and Ohio, where Biden had made a strong play in the final stages of the campaign. But Biden also picked off states where Trump sought to compete, including New Hampshire and Minnesota. But Florida was the biggest, fiercely contested battleground on the map, with both campaigns battling over the 29 Electoral College votes that went to Trump.
The President adopted Florida as his new home state, wooed its Latino community, particularly Cuban-Americans, and held rallies there incessantly. For his part, Biden deployed his top surrogate — former President Barack Obama — there twice in the campaign's closing days and benefited from a $100 million pledge in the state from Michael Bloomberg.
The high-stakes election was held against the backdrop of a historic pandemic that has killed more than 230,000 Americans and wiped away millions of jobs. Both candidates spent months pressing dramatically different visions for the nation's future and voters responded in huge numbers, with more than 100 million people casting votes ahead of Election Day.
Democrats entered the night confident not only in Biden's prospects, but also in the party's ability to take control of the Senate. But the GOP held several seats that were considered vulnerable, including in Iowa, Texas and Kansas. The House was expected to remain under Democratic control.
The coronavirus pandemic — and Trump's handling of it — was the inescapable focus for 2020.
For Trump, the election stood as a judgment on his four years in office, a term in which he bent Washington to his will, challenged faith in its institutions and changed how America was viewed across the globe. Rarely trying to unite a country divided along lines of race and class, he has often acted as an insurgent against the government he led while undermining the nation's scientists, bureaucracy and media.
Trump spoke at the White House at 2.21am (Washington time), saying it was the latest news conference he had ever had, and claimed he had won the election.
"Either they were going to win, or if they didn't win, they'll take us to court.
"This is a fraud on the American public. This is an embarrassment to our country. We were getting ready to win this election. Frankly, we did win this election. So our goal now is to ensure the integrity, for the good of the nation, we want the law to be used in a proper manner.
"So we'll be going to the Supreme Court. We want all voting to stop. We don't want them to find any ballots at 4am in the morning and add them to the list. It's a very sad moment. To me, this is a very sad moment.
"As far as I'm concerned, we already have won it.
"We were winning everything and all of a sudden it was all called off.
"We won states that we weren't expected to win - Florida ... we won it by a lot. The great state of Ohio. Texas.
"We won Texas by 700,000 votes and they don't include it in the tabulation.
"And Georgia... they'll never catch us. They can't catch us.
"Arizona ... we have a lot of life in that ... there were a lot of votes out there we could get.
"We don't need Arizona. That's a state that would have been nice. There's a good possibility ... the numbers have come down. We want that to stay in play.
"Most importantly we are winning Pennsylvania by a tremendous number of votes.
"We are up ... think of this, think of this ... up 690,000 votes in Pennsylvania ... that's not close.
"We are winning Wisconsin ... and we don't need to win all of them.
"All of a sudden I said... what happened to the election.
"They said ... let's go to court ... they were either going to win or if they weren't going to win they want to go to court."
Biden earlier told his supporters "we're on track" to win the election but "we will have to be patient" until all votes are counted. He said a result might be known tomorrow morning (US time) but "it may take a little longer".
Trump early tweeted "we are up big but they are trying to steal the election. We will never let them do it ..."
He said votes cannot be cast after the polls have closed. AP reports that in multiple states, ballots can in fact be counted if they arrive after Election Day.
Trump later deleted the tweet - seemingly to correct a spelling error in which he wrote "poles" instead of "polls" - and said he would make a statement tonight: "A big win!"
Twitter flagged Trump's tweet about the Democrats "trying to steal the election", saying "some of the content is disputed". And Facebook put a label on the post, saying votes were being counted and no winner was yet projected.
The race is so tight Americans may not even know the winner today.
Trump was at long odds with bookmakers to win yesterday, however that changed on Tuesday afternoon (NZ time) and he was listed as the favourite with the Sportsbet and Betfair agencies. By Tuesday evening, the odds had narrowed again and the candidates were almost even.
From coast to coast, races were tight in many states.
Biden picked up the first battleground state of the night, New Hampshire, a small prize that Trump tried to steal from Democrats.
Biden also won California, the nation's biggest electoral haul, and other predictable victories including Colorado and Virginia, two former battlegrounds that have become Democratic strongholds.
Trump won Florida, the nation's most prized battleground state, as he picked up Kansas, North Dakota and other conservative bastions.
The President retained many states he won in 2016 and, as long predicted, the race in part seemed to rest on the three northern industrial states where Trump most surprised the Democrats four years ago - Michigan, Wisconsin and Pennsylvania - as well as Georgia.
Fox News said Biden would win Arizona but the Trump team fired back, saying it was too early to call with more than one million votes still to count.
There were later reports Fox was considering retracting the call, but it stood behind its prediction. Arnon Mishkin, the director of the Fox News decision desk, said they debated it for about half an hour and were confident on their call. "We're not wrong in this particular case."
BDO reports that Biden won Nebraska's 2nd congressional district, which would ensure his victory if he wins Michigan, Nevada, and Wisconsin.
Results in several key battleground states are in flux as election officials processed a historically large number of mail-in votes.
Democrats typically outperform Republicans in mail voting, while the GOP looks to make up ground in Election Day turnout. That means the early margins between the candidates could be influenced by which type of votes — early or Election Day — are being reported by the states.
While there are 50 states in America, when the votes are counted just a handful of them – Florida included – decide who wins the presidential election.
Millions of voters put aside worries about Covid-19 — and long lines — to turn out to vote. They joined 102 million Americans who voted earlier, a record number that represented 73 per cent of the total vote in the 2016 election.
In downtowns ranging from New York to Denver to Minneapolis, workers boarded up businesses lest the vote - or uncertainty about the winner - lead to unrest of the sort that broke out earlier this year amid protests over racial inequality.
Those who voted in person on Tuesday (Wednesday NZT) joined 102 million Americans who voted early, a record total that represents 73 per cent of the total turnout of the 2016 presidential election.
Biden entered election day with multiple paths to victory while Trump, playing catch-up in a number of battleground states, had a narrower but still feasible road to clinch 270 Electoral College votes.
Trump began the day on an upbeat note, predicting that he'd do even better than in 2016, but during a midday visit to his campaign headquarters, spoke in a gravely, subdued tone.
"Winning is easy," Trump told reporters. "Losing is never easy, not for me it's not."
The campaign has largely been a referendum on Trump's handling of Covid-19, which has so far claimed 232,000 lives in the US.
Trump insists the nation is "rounding the turn" on the virus. But Dr Deborah Birx, the coordinator of the White House coronavirus task force, broke with the president and joined a chorus of Trump administration scientists sounding the alarm about the current spike in infections.