How might a Trump legal challenge play out?
Despite the US president saying he intends to go to the Supreme Court because he wants "all voting to stop", there are a number of legal hurdles.
Any case would have to have been initiated in a lower court.
He would need to find a pretext in some state that would let him challenge enough votes to flip the margin.
Mr Biden's lead in Wisconsin of 20,000 votes is considered by some experts to be a "high hurdle" that is too wide for the president to mount a legal challenge on.
Pennsylvania, should Mr Trump lose there, would be the most likely state to trigger a Supreme Court challenge.
Prior to the election, the court declined to block the state from counting ballots received after election day, but it left the door open for the issue to be considered afterwards.
How long could a legal challenge take to resolve?
It took 36 days to settle the outcome of Florida's election in 2000.
"That was an extremely accelerated process," said Christopher Galdieri, a professor of politics at Saint Anselm College in New Hampshire. Even getting it to the Supreme Court could prove problematic, he added.
"It's one thing if you have conflicting court rulings, but if lower courts agree that a Trump case lacks merit, this might not get to the Supreme Court."
What is the likelihood of a Trump victory?
This is hard to call. While the conservative members of the court voiced sympathy with the Republican case in Pennsylvania, the bench has traditionally been reluctant to intervene in matters of state - as opposed to federal - law.
This worked in the Republicans' favour when the court refused to intervene when states were accused of suppressing the vote.
Prof Galdieri thinks the court would be cautious.
"I don't think the Supreme Court is interested in burning its political capital and they have bigger fish to fry," he said.
Will the president's own Supreme Court judge change the outcome?
The appointment of Amy Coney Barrett gives conservatives a majority on the court, but that is not necessarily a guarantee.
In August, Brett Kavanaugh sided with liberals in turning down a plea from Rhode Island Republicans to overturn the state's decision to waive ballot security measures because of coronavirus.
Is there a legal precedent for a challenge?
The obvious precedent is the contested election between George W Bush and Al Gore.
However, according to Prof Galdieri, the case in the 2000 election is very different from what might arise this time around.
In that election, Florida was using ridiculous punch cards that were prone to error and opened the door to all sorts of controversies over dimpled chads and other issues.
"The question of what ballots should be counted and how they should be interpreted was one that lent itself readily to legal controversy. We don't yet have these sorts of issues in this election," said Prof Galdieri.
What other options does Trump have?
The Trump campaign has indicated it intends to push for a recount.
Candidates can request a full or partial vote recount in a state if the margin separating the candidates is one per cent or less.
An automatic recount will be triggered in Michigan if the margin separating the two candidates is 2,000 votes or fewer.
In Nevada, a candidate can request a recount for any reason, regardless of the margin of victory.