One Friday afternoon last month a group of politicos logged on to Zoom, a video conference platform, to war-game what could happen after the US election. Among them were senior figures who had previously served in the White House, Pentagon, Homeland Security and Congress.
They were split into teams. Some acted as employees of US President Donald Trump or his Democratic rival Joe Biden, making arguments accordingly. Others would play the Republicans or Democrats in Congress, or represent the media or the courts.
The scenario given for the exercise - a technique commonly used in government and business to plan for crises - was a simple one: What if on the morning after the US election it was not clear who won?
Imagine postal votes in Wisconsin, North Carolina and Michigan are still being counted, participants were told. Without results from those three critical battleground states the outcome hangs in the balance. What happens next?
Over the next four hours each team argued their case, with adjudicators rolling a 10-sided die to decide conflicts and carrying the scenario on. Trump's team decided he would fight his corner with all tools at his disposal.
Within 48 hours, the president ordered the head of the postal service, one of his appointees, to stop delivering postal ballots. Within a week he used the two-centuries old Insurrection Act to deploy troops to protect counting stations.
As November turned to December legal challenges mounted and protests erupted but no clarity emerged. By January 20, inauguration day, neither side had backed down.
"We were all sort of sitting there, looking at each other, staring at the screen saying 'holy s***'", recalled one participant. America was in a constitutional crisis.
'The doomsday scenario'
Such sessions, known as 'table tops' or 'war games', by their very nature involve imagination, thinking through scenarios which may not come to pass. Yet the issues grappled with that June afternoon are the same ones now being discussed with increasing volume in Washington DC.
With just four months to go until voting day, a question once considered unthinkable is now being asked: What if the US president does not accept election defeat?
To understand how seriously the concerns are being taken, and how widespread they are shared, the Telegraph talked to close to 20 well-placed individuals, including members of Trump's Republican party.
Among them were current and former US congressmen, former senior figures in the Pentagon, intelligence agencies and past US administrations as well as academics working on mapping out worst-case scenarios.
What emerged was a deeply felt worry - some said without modern comparison - that the president could pull legal, governmental and political levers to remain in power if Biden fell short of a blowout victory.
Some predicted lawsuits over the increased use of mail-in ballots amid coronavirus. Others thought Trump could misuse executive powers for his own benefit. Multiple people feared a tweet calling on his supporters to take to the streets.
"If the result is close, he is going to fight like a steer," said Christie Whitman, the former Republican governor of New Jersey. Academics warned of a "doomsday scenario" or a "perfect storm of bad things happening".
Tom Coleman, former Republican congressman from Missouri, said: "From what we have experienced during Trump's 3.5 years in the presidency, one must assume he is capable of doing anything to stay in office."
Planning for the worst
The war-game session was run by the Transition Integrity Project. It was created by two academics, Nils Gilman, a historian who has run scenario planning exercises for the US government for years, and Rosa Brooks, a law professor at Georgetown University.
The identities of those who take part is closely guarded - they have not been named publicly and participants are barred from speaking about the sessions. Its existence has only recently emerged.
It is understood members include two former governors, a former US cabinet minister, ex-chiefs of staff to a US president and vice president as well as retired members of the Pentagon and Congress - a sign of how seriously its work is taken.
The group actually held four individual role-playing exercises last month, each mapping the fallout to different election outcomes. Only in one, a massive Biden victory, did Trump not seek to remain in power.
"There were four big takeaways from me from the games," said Gilman, who discussed broad learnings but declined to talk publicly about the details of the exercises.
"First, unless Biden wins by a landslide there's going to be a constitutional crisis and likely political violence. Second, if it is at all close Trump has perfectly legal ways to challenge the election if he and the Republican Party choose to.
"Third, the Biden campaign needs to understand that election day is not the finish line, the inauguration is. And fourth, neither the Supreme Court nor the military wants to touch any of this with a 10-foot pole."
The bipartisan group's focus has been the 78 days between the election on November 3 and the inauguration on January 20, when at noon the US Constitution demands that a president leaves office.
Unlike in Britain, when elections result in an immediate switch of government, the American presidential hand-over is staggered - a quirk of the US electoral system. That means Trump is in the Oval Office during the period with his hands on the levers of power.
Trump has waved away suggestions he would not accept a defeat. "Certainly, if I don't win, I don't win," the President told Fox News recently, saying he would "go on" and "do other things". His allies have done likewise, one supportive senator calling the idea he could cling on "nutty stuff".
Yet Biden, the presumptive Democratic nominee, disagrees, recently predicting the military may intervene should Trump lose the election but refuse to leave office. He told TV host Trevor Noah: "I am absolutely convinced they will escort him from the White House with great dispatch."
'What would the army do?'
Stories shared with the Telegraph reveal that at least some Republicans in Congress and figures in the US military circle have a deep disquiet about how Trump could act if the election does not go his way.
Lawrence Wilkerson, a retired army colonel who was chief of staff to secretary of state Colin Powell, recalled a meeting with a Republican senator last autumn. The topic for discussion was the Yemen civil war but at one point it unexpectedly changed.
"He asked me to dismiss all of my colleagues and he dismissed his legislative affairs guy and his chief of staff," Wilkerson said of the senator. "We were alone in his office and he prefaced it with 'I just want to talk to you for a moment as a military professional'."
"He said 'I want to ask you a question. If things were really to go sour and the president loses and refuses to leave, or leaves and in either case calls a lot of his base to the streets and they come armed, what will the US military do?"
Wilkerson had time to unpack the polling on how soldiers voted and warn that such a situation would show the US political system had "utterly abysmally failed" before a congressional vote ended the conversation.
Once, Wilkerson said, he had thought it impossible that Trump could call his supporters onto the streets with guns but now he is not so sure. "I don't think it's probable, but just the fact that it's possible scares me," he said.
Guy Snodgrass was serving in the Trump administration until two years ago, when he stepped down as communications director to Jim Mattis, then US defence secretary, but he remains in touch with old colleagues.
He said that in recent months three different senior figures - one colonel, one captain and one rear admiral - had all expressed fears that Trump could ask the military to do things after the election that would be unpalatable.
"President Trump has been willing, as we've seen consistently for the last three-and-a-half years, to put people in very precarious positions, making them choose between personal loyalty to him and professional loyalty to the country," he said.
"That is what everyone is terrified of. People are worried about getting into a situation where they are seen to be throwing out a president and getting dragged into a political food fight."
Numerous ex-government figures pointed to the handling of recent anti-racism protests, which saw crowds being forcibly cleared near the White House for a presidential photo-op by a church, as a cause for concern.
Apparent tensions between the president and military leaders burst into public view, with the chairman of the Joint Chiefs of Staff apologising for appearing in the photo-op, the defence secretary publicly opposing the use of active soldiers and ex-military chiefs condemning Mr Trump.
Jeff Flake, the Republican senator for Arizona until last year and a prominent Trump critic, spoke to the tensions when asked if he had picked up unease between the president and his military chiefs when in the Senate.
"Oh yes, oh no doubt," Flake told this newspaper. "To a person, yes. That was reflected in the briefings that we got officially and certainly it was reflected in private meetings that many of us had."
Flake does not have concerns Trump will try to cling on after a defeat, however, believing the backing he would need - including from Republicans in Congress - would not be there.
"It's not that I don't think the president would be inclined to do that. I just don't think that there are any significant institutions that would support him," Flake said.
He said of his old Republican congressional colleagues: "If the President's hoping that the same supporters, particularly those in leadership positions, would be inclined to help him overcome a genuine election, it's not going to happen."
Beyond Capitol Hill and the Pentagon, there are fears in intelligence circles too.
Gen Mike Hayden was director of the National Security Agency (NSA) under presidents Bill Clinton and George W Bush - one Democrat, one Republican - before serving as the latter's CIA director.
"I am worried this president will say the result is impossible and the election was rigged," Gen Hayden said, going on to mention the razor-tight 2000 election between Bush and Al Gore, which ended up in the Supreme Court.
For weeks the winner was not clear, with all focus on Florida amid debate about whether the infamous "hanging chad" ballots should be counted. Gore ended his challenge when the Supreme Court stopped the Florida recount.
"We had something similar 20 years ago when Bush was elected but he and Al Gore were honourable men. This president is not honourable," Gen Hayden said.
"I think the Democrats will win and this president will say it is not right. And then I don't know what is going to happen."
He said similar concerns about the President's behaviour were voiced at a gathering he attended recently with 10 other former CIA, NSA and Defence Department figures.
'A witches brew of uncertainty'
But what could actually happen? Among those that gave their views, two consistent messages emerged. One, the larger Biden's victory, the less likely a Trump challenge. And two, any lawsuit will probably focus on postal votes.
This election cycle is set to see a dramatic increase in mail-in votes on account of Covid-19, with many state legislatures and governors, who tend to oversee election rules, sending out more given the risks of in-person voting.
Yet the President is fiercely critical. Trump recently tweeted that mail-in ballots "will lead to the most corrupt election in USA history", a message he has echoed repeatedly in recent months. His campaign team sued to stop an expansion in Pennsylvania this month.
Trump argues mail-in ballots are vulnerable to fraud. Critics claim he sees them as more likely to result in Democratic votes - though the evidence is mixed on that point. Some see the laying of the groundwork for questioning the result.
Norman Ornstein, a scholar with the think tank American Enterprise Institute and a member of the National Task Force on Election Crises, another bipartisan body doing worst-case election planning, is concerned about the timings of result declarations.
Normally states have maybe 4 or 5 per cent of their electorate voting by mail, Ornstein said, but this year that figure could be closer to 20 per cent.
"We may have election results that don't come in for a week, 10 days or more after the election because it takes so long to count them," Ornstein said.
"We know that the President wouldn't hesitate if he lost under those circumstances to cry foul and say the election was rigged."
The delayed counts could add to the confusion. One fear is that the media could call a state one way on election night, only to backtrack and hand it to the other candidate after postal ballots are counted, fuelling conspiracies.
Another possibility is that Trump could call on states to stop counting postal ballots because they were illegitimate - something he came close to doing in one close race during the 2018 midterm elections.
"The Florida election should be called in favor of Rick Scott and Ron DeSantis in that large numbers of new ballots showed up out of nowhere," Trump said then, name-checking the Republican candidates for the Senate and governorship as counting continued. He claimed" an honest vote count is no longer possible".
A whole other raft of possibilities remain. Given the idiosyncrasies of the electoral college system it is even theoretically possible state electors could defy the votes cast by residents and pick another candidate - though such a move would be deeply controversial.
Some have already turned to lawyers for advice. Coleman, the ex-Republican congressman, was so concerned that he contacted a leading constitutional scholar about the mechanism for forcibly removing Trump from office.
"For over 200 years the above have probably never been thought about," the scholar wrote back, according to Coleman. "But we do not live in normal times and Trump is certainly not a normal president. We must be prepared for the unthinkable."
One sitting Republican warned that with postal vote changes, coronavirus and the recent civil unrest there was "a witches brew of uncertainty" around the election. "I fully anticipate there will be legal challenges all over the place, just like there was in 2000," he said.
In the end, none of this may come to pass. Trump may win comfortably and carry on to a second term. Biden could win comfortably - as his 9-point poll lead suggests he could - and the president may leave office without protest.
Even so, the team behind the war games see value in their work. They hope to share their learnings from the exercises with decision-makers in the election process such as state governors, voting administrators and broadcast bosses.
"The purpose of these exercises isn't just to give people nightmares about the dissolution of America but to make sure this doesn't happen," said Brooks, who co-founded the Transition Integrity Project.
"The hope was that these exercises could prevent these catastrophic outcomes."
In less than 130 days we will find out if that has proved correct.