There’s no such thing as a joke, that’s what Freud said.

In his snappily titled 1905 tome ‘The Joke and its Relation to the Unconscious’, he posited that jokes allow us to “express sexual, aggressive, playful, or cynical instincts that would otherwise remain hidden”.

So what should we make of Donald Trump’s tweet this morning, in which he joked about defying the constitution to serve more than two full terms in office?

While many of Sigmund’s theories are now widely mocked or discounted, others have become fundamental tenets of psychology. And we’ve all used humour to convey an opinion or intention we’re uncomfortable with.

We might joke about the acquaintance who conveniently disappears when it’s his turn to buy a round, slapping him on the back and saying, “Only kidding, mate” but quietly hoping they sense our frustration at their cheapskate ways. Or we’ll ask whether our date “got lost“ after turning up 20 minutes to Nandos, leaving us to fiddle with halloumi fries as nearby tables ponder whether we’ve been stood up.

Which is why we should be worried when the president of the United States — a man with a famous (or infamous) distaste for rules and convention — jokes about defying the ultimate rulebook: the US constitution.

The framers of the constitution didn’t set term limits; George Washington established the convention when he stepped down after two terms.

It was only after the chaos of the Second World War gave cover for Franklin D Roosevelt to run for — and win — four consecutive terms that Congress decided to enshrine the convention in law.

With Trump’s gaudy golden temples, and many of his most ardent supporters calling him the best president ever, it would hardly be surprising if he saw himself as a modern-day Ozymandias, a king of kings who should be allowed to serve longer than any man before him.

Donald Trump shares Time Magazine meme on Twitter

But it’s likely even Trump knows that altering the constitution in his favour is prohibitive — but his repeated undermining of a key presidential norm brings to mind a potentially more likely and worrying prospect.

It was a once-unthinkable scenario, but now people are openly beginning to wonder whether it could come to pass: the president refusing to leave office if he loses in 2020.

Michael Cohen, once one of The Donald’s closest confidants, said under oath this year: “Given my experience working for Mr Trump, I fear that if he loses the election in 2020 there will never be a peaceful transition of power.” It’s a prospect Nancy Pelosi has acknowledged and said her party needs to prepare for.

Even in the face of multiple bankruptcies, Trump has spun every defeat as a victory. A 2020 loss would be the only one he couldn’t obscure. Or could he?

Earlier this year, a reporter at The Independent asked constitutional experts what would happen if the president refused to step down after losing an election. Those constitutional experts were stumped.

One imagined a scenario where Trump loses by a single per cent, causing him to cry voter fraud and squat in the mansion at 1600 Pennsylvania Ave.

“If he wants to stay in the White House, he would stay in the White House,” another said.

The Democrat challengers to Trump in 2020 Show all 25 1 /25 The Democrat challengers to Trump in 2020 The Democrat challengers to Trump in 2020 Bernie Sanders The Vermont senator has launched a second bid for president after losing out to Hilary Clinton in the 2016 Democratic primaries. He is running on a similar platform of democratic socialist reform Getty The Democrat challengers to Trump in 2020 Joe Biden The former vice president recently faced scrutiny for inappropriate touching of women, but was thought to deal with the criticism well and has since maintained a front runner status in national polling EPA The Democrat challengers to Trump in 2020 Elizabeth Warren The Massachusetts senator is a progressive Democrat, and a major supporter of regulating Wall Street Reuters The Democrat challengers to Trump in 2020 Amy Klobuchar Klobuchar is a Minnesota senator who earned praise for her contribution to the Brett Kavanaugh hearings Getty The Democrat challengers to Trump in 2020 Michael Bloomberg Michael Bloomberg, a late addition to the 2020 race, announced his candidacy after months of speculation in November. He has launched a massive ad-buying campaign and issued an apology for the controversial "stop and frisk" programme that adversely impacted minority communities in New York City when he was mayor Getty Images The Democrat challengers to Trump in 2020 Tulsi Gabbard The Hawaii congresswoman announced her candidacy in January, but has faced tough questions on her past comments on LGBT+ rights and her stance on Syrian President Bashar al-Assad Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Pete Buttigieg The centrist Indiana mayor and war veteran would be the first openly LGBT+ president in American history Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Deval Patrick The former Massachusetts governor launched a late 2020 candidacy and received very little reception. With just a few short months until the first voters flock to the polls, the former governor is running as a centrist and believes he can unite the party's various voting blocs AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Beto O'Rourke The former Texas congressman formally launched his bid for the presidency in March. He ran on a progressive platform, stating that the US is driven by "gross differences in opportunity and outcome" AP The Democrat challengers to Trump in 2020 DROPPED OUT: Kamala Harris The former California attorney general was introduced to the national stage during Jeff Sessions’ testimony. She has endorsed Medicare-for-all and proposed a major tax-credit for the middle class AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Bill De Blasio The New York mayor announced his bid on 16 May 2019. He emerged in 2013 as a leading voice in the left wing of his party but struggled to build a national profile and has suffered a number of political setbacks in his time as mayor AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Steve Bullock The Montana governor announced his bid on 14 May. He stated "We need to defeat Donald Trump in 2020 and defeat the corrupt system that lets campaign money drown out the people's voice, so we can finally make good on the promise of a fair shot for everyone." He also highlighted the fact that he won the governor's seat in a red [Republican] state Reuters The Democrat challengers to Trump in 2020 DROPPED OUT: Cory Booker The New Jersey Senator has focused on restoring kindness and civility in American politics throughout his campaign, though he has failed to secure the same level of support and fundraising as several other senators running for the White House in 2020 Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Wayne Messam Mayor of the city of Miramar in the Miami metropolitan area, Wayne Messam said he intended to run on a progressive platform against the "broken" federal government. He favours gun regulations and was a signatory to a letter from some 400 mayors condemning President Trump's withdrawal from the Paris Climate Accord Vice News The Democrat challengers to Trump in 2020 DROPPED OUT: Kirsten Gillibrand The New York Senator formally announced her presidential bid in January, saying that “healthcare should be a right, not a privilege” Getty The Democrat challengers to Trump in 2020 DROPPED OUT: John Delaney The Maryland congressman was the first to launch his bid for presidency, making the announcement in 2017 AP The Democrat challengers to Trump in 2020 DROPPED OUT: Andrew Yang The entrepreneur announced his presidential candidacy by pledging that he would introduce a universal basic income of $1,000 a month to every American over the age of 18 Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Julian Castro The former San Antonio mayor announced his candidacy in January and said that his running has a “special meaning” for the Latino community in the US Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Marianne Williamson The author and spiritual adviser has announced her intention to run for president. She had previously run for congress as an independent in 2014 but was unsuccessful Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Eric Swalwell One of the younger candidates, Swalwell has served on multiple committees in the House of Representatives. He intended to make gun control central to his campaign but dropped out after his team said it was clear there was no path to victory Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Seth Moulton A Massachusetts congressman, Moulton is a former US soldier who is best known for trying to stop Nancy Pelosi from becoming speaker of the house. He dropped out of the race after not polling well in key states Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Jay Inslee Inslee has been governor of Washington since 2013. His bid was centred around climate change AFP/Getty The Democrat challengers to Trump in 2020 DROPPED OUT: John Hickenlooper The former governor of Colorado aimed to sell himself as an effective leader who was open to compromise, but failed to make a splash on the national stage Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Tim Ryan Ohio representative Tim Ryan ran on a campaign that hinged on his working class roots, though his messaging did not appear to resonate with voters Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Tom Steyer Democratic presidential hopeful billionaire and philanthropist Tom Steyer is a longtime Democratic donor AFP/Getty

Like the two-term convention pre-war, the peaceful transfer of power hasn’t had to be written into law — but it was woven into the fabric of American politics.

Another constitutional expert we asked said that in the event of a refusal to transfer power in 2020, it would be left to Congress to pressure the president out. To which I’d say: Yeah, good luck with that.

Whatever the outcome, and whatever the measures taken, such a scenario would be a constitutional crisis of the highest magnitude. America would be changed forever.

Both Barack Obama and Ronald Reagan mentioned in passing that they regretted they could only serve two terms. Donald Trump repeatedly goads America over that very prospect.