Vice President Kamala Harris, her campaign team and some of Donald Trump’s own allies say they expect the former president to quickly declare victory on election night — even if the outcome is not yet settled in key swing states.

Between the time it takes to process mail ballots and deal with provisional ballots in some battleground states, votes will not be fully tabulated on election night. Projections of who won a close presidential race might not come for days, similar to the 2020 election.

NBC News spoke to four Trump allies, all of whom speculated that the former president may be prepared to pull a repeat of 2020 and quickly declare he is the victor on election night when that is not yet certain. The sources all noted they did not have direct knowledge that this was a formal Trump campaign plan.

Others noted that this November could be different because he is surrounded by a new slate of top aides who wouldn't push him to make such a declaration.

Seven Harris aides — and the vice president herself — said they are making preparations if Trump does indeed prematurely say he won or if he legally challenges the results if he loses.

The Trump campaign did not respond to a request seeking comment.

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Such a move could signal to Trump's supporters that he has won and create skepticism that any votes that come in after Election Day are illegitimate and signs of unproven fraud.

“Of course,” Harris told NBC News in an interview Tuesday when asked if her campaign is preparing to deal with Trump declaring an early victory. “This is a person, Donald Trump, who tried to undo a free and fair election, who still denies the will of the people, who incited a violent mob to attack the United States Capitol and 140 law enforcement officers were attacked.”

“100%,” a former Trump adviser said when asked what the person thought the odds were that the former president would prematurely say he won. “Duh! Is the pope Catholic? There are few things in politics I would ever say you could make a firm bet on. That is one of those.”

An early declaration of victory could be facilitated by what’s known as a “red mirage.” That happens when Republicans appear to have a lead on election night because in-person votes are generally counted quickly — but that lead could disappear in the days after Nov. 5 as absentee and early voting ballots are counted.

In 2020, Trump quickly proclaimed victory on election night, even though he ultimately ended up losing to Joe Biden.

One longtime Republican and Trump supporter said that when they talk to other Republicans, there’s a widespread belief that the former president will claim a win on election night no matter what.

“I’ve heard this from like 10 different people,” the person said, making clear they didn’t have direct knowledge of Trump’s plans. “Because of the way things are counted, there is likely no way Democrats can possibly be ahead in places like Pennsylvania and Wisconsin on election night.”

“He’s going to be able to use what the Democrats called the ‘red mirage’ in 2020,” added this person who, like others in this article, were granted anonymity to speak candidly.

Trump is still casting doubt on the 2020 election, and the false notion that it was stolen from him through cheating by the Democrats has been a rallying cry for his supporters throughout this campaign. He also continues to push the false narrative that noncitizens will vote in the 2024 election and tip the scales against him.

Beyond the fact that Trump has employed a similar strategy in the past, the likelihood of a “red mirage” play is exacerbated by the fact that key swing states such as Pennsylvania, Wisconsin, Michigan and Georgia don’t start counting mail ballots until Election Day.

“That window of time between the polls closing and races being called, I think, has shown to be a real vulnerability, where people seeking to undermine confidence in those results if they’re going to lose have really exploited,” Al Schmidt, Pennsylvania’s top election official, told CBS’ “60 Minutes” earlier this month.

Harris and other Democrats have been ringing alarm bells about the possibility that Trump could declare a premature election win, but even Republican supporters of the former president fully expect his campaign to consider the move.

“There is no part of me who does not think that is part of the conversation,” said a Trump donor in the key swing state of North Carolina. “We have seen him do it before, and if he is up on election night, I think his campaign — maybe smartly — will try it again.”

Others do think that Trump has more to consider and different voices in his ear than 2020, and that multiple factors will be considered.

“Last time, he got spun up by Rudy Giuliani,” a former Trump adviser said, referring to the former New York City mayor’s role in pushing election conspiracy theories as Trump’s lawyer in the aftermath of the 2020 election. “That’s not going to happen. So who is going to spin him up this time?”

The person said that top campaign advisers Susie Wiles and Chris LaCivita are not going to do that, and there is a sense among Republican supporters that his team of close advisers will attempt to stifle any attempt to allow Trump to claim victory if it is not clear he won.

An attorney who worked for Trump in both 2016 and 2020 said that a key indicator will be the types of lawyers he has around him in the final days of the campaign and on election night and beyond. Those with big pedigrees who work for well-known law firms are less likely to risk their reputations on political shenanigans.

“The thing to watch is what attorneys will end up being around him. I was in this for two cycles with him,” the former Trump attorney said. “The difference in lawyers was incredible. It was night and day, the difference between 2016, when he had the best law firms and lawyers in the country, versus 2020.’”

Roger Stone, a longtime Trump ally who continues to advise him politically, says that there are past examples of presidential advisers telling candidates to call an early election win, including James Baker and George W. Bush in 2000, and Joseph Kennedy telling his son John F. Kennedy to pull a similar move in 1960.

In documentary footage of election night in 2020, Stone is caught on tape advising Trump to declare victory even if the results are in doubt.

“I suspect it will be, I really do suspect it will be up in the air,” Stone said at the time. “When that happens, the key thing to do is to claim victory. Possession is nine-tenths of the law. Now, we won, f--- you.”

“When I said it in 2020, I was accused of saying that Trump should declare victory even if he ‘lost,’ which is not even remotely what I said,” Stone told NBC News. He did not specify whether he was urging Trump to call an early win for himself this year.

He added that he was simply following a well-worn path blazed by past presidential advisers. The comment did become a piece of evidence used by the House Jan. 6 committee in 2022, when trying to show that Trump wanted to claim prematurely that he had defeated Biden.

Harris aides told NBC News that they do not just anticipate Trump will claim victory on election night even if the outcome remains in question — or legally challenge the results if he loses — but they are also actively planning for that scenario.

“There is nobody on the campaign who believes the election will be done on Election Day,” one longtime aide said.

Campaign officials instead have been preparing for results to be known within a few days of Election Day, but the big question will be whether a legal challenge ends up deciding the election. To that end, the Harris campaign has been assembling a team of lawyers to fight back against Trump lawyers should the former president lose but then try to get the results overturned through the courts.

There is no anticipation, even from her own team, that Harris will talk on the campaign trail about the fact that the courts might ultimately end up deciding the election because they don’t want to depress voters with the idea that their votes could ultimately get thrown out by a judge sympathetic to Trump.

“People need to go out and vote,” the aide added. “You don’t want people thinking about legal challenges.”

A second Harris aide who requested anonymity to speak about Harris’ election week plans said the campaign and Democrats are looking at the 2000 election, as well as the 2020 election, and steeling themselves for what could be a legal fight with Trump.

“We are not doing 2000 again,” the person said. “She is a fighter. Like ‘I eat no for breakfast. I knock down doors.’ That is Kamala Harris. She is a very strong human being and there is a whole legal team focused on this.”

The person underscored that Harris is a trained attorney and she’s thought about Trump possibly trying to contest the election results in the courts. But the campaign is also focused on “closing gaps” so that the race isn’t even close enough that a legal challenge in one state would affect the outcome of the whole election.

Polls show a neck-and-neck race, with razor-thin polling margins in key battleground states. But while Harris and her allies have been portraying the vice president as the underdog in the race, Trump’s messaging has been less nuanced and more focused on the idea he will win, which sends signals to supporters that any outcome where he does not is fraudulent.

“She is a threat to democracy,” Trump said Monday. “She’s a threat to a lot of things but that’s the way it has to be, because we are winning by a lot. We are leading by a lot. We are leading in the polls.”

“Every single state,” he added.