He has been waging a months-long campaign against mail-in voting in November by tweeting and speaking critically about the practice, which has been encouraged by more states to keep voters safe amid the coronavirus pandemic.
In a July interview, the president similarly refused to commit to accepting the results. “I have to see. Look … I have to see,” he said on Fox News Sunday. “No, I’m not going to just say yes. I’m not going to say no, and I didn’t last time either.”
Now, a question once considered unthinkable is being asked: What if the US president does not accept election defeat? Is there a contingency plan in case the president and his supporters refuse to go quietly?
What time will we know the US election winner?
Election night may not deliver the definitive winner the public has come to expect. The unprecedented number of mail-in ballots this election, prompted by Covid-19, could cause significant delays. While some states start counting postal ballots before Election Day, some wait until the polls close.
Initial results in states that prioritise the counting of in-person votes may show Mr Trump ahead, only for Mr Biden to appear ahead later as the postal vote tallies come in.
If there is no clear winner on the night, counting could take days, or even weeks, although most officials in the vital swing states have said they hope to have declared a result by the weekend after the election at the latest.
No matter the final result, Mr Trump will remain in the Oval Office after the election if he loses. He will officially become a “lame duck” president, with 73 days of his term to serve out before handing over the keys to the White House.
On January 20, 2021, the new president will deliver his inaugural address. This has traditionally been held on the steps of the US Capitol building, but it remains unclear what form of national address would occur if the pandemic still poses a risk to the public health.
How does the electoral college work?
Each state is represented by a number of votes in the Electoral College which roughly correlates with the size of the population; for example, Florida has 29 votes and California has 55. There are 538 in total, so 270 are needed to win.
In all but two states, the candidate who wins the public vote will win all the Electoral College votes for that state. These votes are cast by electors – there is one elector for every college vote – on December 14.
The structure of the Electoral College, combined with the political and demographic makeup of swing states, means a few states carry disproportionately more weight in an election and sometimes overrule the popular vote.
Read more: The 2020 US electoral college explained
Results from the swing states: