Following Trump’s cancellation of his appearance at the correspondents' dinner, it’s not certain if the press corps will survive much longer

While it isn’t always easy to be a huge fan of Donald Trump’s manners, his harshest etiquette critic should allow him this. The Donald is not one to leave a dinner cancellation to the last minute.

Here he has the edge over Ronald Reagan. In 1981, Reagan rudely waited until early April to pull out of the White House correspondents’ dinner – the annual celebration of journalism and First Amendment-enshrined free speech where the president does an amusing stand-up turn, and is roasted by a comedian in return.

Reagan’s excuse, if you can dignify it as such, was that he had been shot in the gut on 30 March, and wasn’t feeling so hot.

Trump bravely refused to give a feeble explanation for the first presidential no-show in 26 years. Giving a generous ten weeks’ notice, he simply tweeted that he won’t be going on 29 April and added that “everyone should have a great evening”.

As so often with Trump, the battle between his stoicism (in avoiding any flimsy excuse) and graciousness (in hoping his truancy won’t spoil the fun) is too close to call.

Yet out there in Fakenewsland, cynics will misinterpret his motives for becoming the first un-shot president to play hooky since – can anyone guess? Go on, have a crack. You can rule out JFK, FDR and anyone on Mount Rushmore, if it helps – Richard M Nixon in 1972.

These sneerers will point out that Nixon was engaged in a deathly struggle with a hostile media at the time. They might accuse Trump of a tactical error in inviting comparison with a scandal-ridden paranoiac whom the stellar reporting of The Washington Post (the paper which recently saw off Mike Flynnovic) would later force to resign.

Yet even if he can’t spell the word, Donald J Trump doesn’t believe in precedent. Dictatorial demigods never do. The first, last and only of their breed in their own estimation, they are immune from the laws that govern politically frail mortals.

So it is that Trump ratchets up this hyper-Nixonian war against the media with no visible concern that it may develop not necessarily to his advantage. In the space of a few days, he has called traditional media enemies of the people; had press patsy Sean Spicer ban CNN, The New York Times, the BBC and other mainstream news organisations from a White House briefing; and pulled out of a dinner engagement regarded for almost a century as obligatory for the president.

God knows how he plans escalate the hostilities to DefCon2. But the big question about the dinner isn’t who will represent the President of the United States (Alec Baldwin in Saturday Night Live mode? The guy who plays a bare-chested Putin on SNL? The real Putin? A tub of orange lard?).

The main question is whether a recognisable White House press corps will survive until the end of April. At the current rate of progress, every media outlet other than Fox, Breitbart, a couple of other white supremacist outlets and a few doolally Christian networks will find itself banned from the building by Wednesday afternoon.

Even the heroic Spicer may not sate his boss’s appetite for gushing sycophancy for long. Trump may want to look to Labour frontbencher Cat Smith, the genius who praised losing Copeland to the Government by 2,000 votes as an “incredible achievement”.

While Cat might spin Trump’s refusal to attend the press dinner as incredible act of courage, to some it looks like cowardice, and to others ingratitude. After all, he owes this event so much.

It was there in 2011 that Barack Obama made merry with Trump’s birtherism and a celebrity episode of The Apprentice. The Donald, said Obama, had a really tough job working out who was to blame for screwing up a barbecue, but after sparing Meat Loaf he fired Gary Busey. “And these,” punchlined the Prez as the camera dwelt on an icily livid Trump, “are the kind of decisions that would keep me up at night.”

The decision that kept him up that particular night was whether to send in the Navy Seals to assassinate Osama Bin Laden in Abbottabad. Obama left the press dinner for the Situation Room, and put his presidency on the line.

He got away with that one. But in wickedly taunting Trump a few hours before his single greatest triumph, did he sow the seed that has lately flowered into the tangerine triffid now threatening to devour Obamacare, the nuclear deal with Iran and all his other major achievements? Did that humiliation decide Trump to seek the presidency and avenge himself by destroying the Obama legacy?

If so – if he really is that petty and destructively vengeful – it’s probably as well the old boy prefers to stay away on 29 April. If the comedian hired to roast him subjected Trump to the kind of astoundingly brazen satirical abuse Stephen Colbert dealt a mutely horrified George W Bush in 2006 – this President could head back to the White House to check how the fake news outlets were reporting the dinner, and fire a couple of cruise missiles at CNN headquarters in Atlanta.