There's an internet adage called Godwin’s law.
It’s named for an American lawyer, Mike Godwin, who originated the phrase in the early days of online discussion groups.
It basically says that it is unwise and irresponsible to make easy comparisons between current events on one hand and Nazism and the Holocaust on the other.
I buy that. It’s too easy, a lot of the time, to make those extreme comparisons to make a point.
They can result in trivialisation of the profound assault on human values represented by Hitler, his acolytes, and all they did and stood for.
But there’s also a deranged US president called Donald Trump.
Last Saturday was Armed Forces Day in the US.
It has been celebrated since around the time of the Korean War, and is seen as a way of honouring the contribution made by the US army, navy, and air forces.
There are armed forces days all over the world, but the US often makes a big fuss, and traditionally celebrates it on the third Saturday in May.
It’s a day on which something is expected of the commander-in-chief. You can search on the web and you’ll find speeches and proclamations by every US president from Truman to Obama.
Some moving, some commonplace, all solemn.
But never anything like the way Armed Forces Day was celebrated this year by the current commander-in-chief.
This man, who never served a day in the military in his life, avoiding the Vietnam War-era draft because of a spurious medical condition, celebrated by sending a tweet to his 80m followers.
The tweet was a film — or rather, an extract from a film.
You probably know the movie, Independence Day, where the world is threatened by horrible-looking aliens in very large spaceships, and then rescued by a fightback led by the US president, played by the actor Bill Pullman.
Before the final battle, Pullman makes a stirring speech to his gathered rag-tag of an army, inspiring them to unending greatness.
Only in the version tweeted out by the leader of the free world, Pullman is replaced by Trump himself.
This man who evaded military service uses Twitter to make himself the hero of a battle to save the world — on a day when he should be paying tribute to men and women who fought and suffered for their country.
It’s phoney, cheap, ugly. It’s yet another demonstration of the supreme narcissism of the man.
Nearly 90,000 Americans have died of Covid-19, and he is portraying himself as a war hero.
What follows next is worse. It’s the start of something that may well dominate public discourse for a good deal of the year.
If it does, it will drag that discourse, and the path of democratic politics, into a dark and slimy gutter from which there may be no coming back.
The next tweet Trump put out for his followers — and it was still there as I was writing this — consisted of one word. Obamagate.
If you don’t know what Obamagate is, you have something in common with the great majority of people in the world. And with the vast majority — well over 99% — of responsible and serious journalists in the world.
Because there is no Obamagate. It doesn’t exist.
If you were a follower of Trump, you mightn’t believe that. Or if you followed some of the nuttier news commentators in the US.
Instead you might think there was some kind of deep scandal, that you couldn’t quite put your finger on, involving Barack Obama.
Apparently Obama conspired to rob Trump of the presidency by planting lies about Russian collusion in the election.
When that didn’t work, he set up the Mueller investigation with more lies.
And when that didn’t work, he did everything he could to frustrate Trump’s heroic efforts to prevent the pandemic damaging America.
You think I’m kidding? There are people in America trying to spread that horse manure.
There are even some who believe it. Some of Trump’s more passionate followers even think that Obama had something to do with the start of the pandemic in China.
The really dangerous thing about this is that it’s not a joke.
The democratically elected current president of the US has seized on this farrago of fanciful lies, and has now accused Obama of corruption and treason.
He has gone public to say that his predecessor should face prosecution and jail time.
Now, of course he’s not campaigning about Obama. He’s going to have to campaign against Obama’s vice-president, Joe Biden.
So this — Obamagate — is phase one of a campaign designed to paint the picture that the Obama White House was corrupt. Phase two will be designed in whatever way succeeds in snaring Biden in the corruption.
But here’s the thing. The Obama White House wasn’t just the least corrupt White House in the last 60 years or more.
There was no corruption. Full stop. It was uniquely boring and corruption-free.
So this campaign — which has Trump’s full backing — depends on the biggest lie in American political history.
It depends on a conscious, deliberate effort to subvert and corrupt the democratic process.
There’s a principle, and it goes like this. The bigger the lie, the more credibility it has.
Because the broad masses of a nation are always more easily corrupted, because in the primitive simplicity of their minds they more readily fall victims to the big lie than the small lie.
I’m quoting that principle almost verbatim from a book called Mein Kampf, written by a man called Adolf Hitler.
He was aided, of course, by an acolyte called Josef Goebbels, who famously said: “If you tell a lie big enough and keep repeating it, people will eventually come to believe it … The truth is the mortal enemy of the lie, and thus … the truth is the greatest enemy of the State.”
Truth is the enemy of Trump’s re-election, and that’s where Godwin’s law comes in.
For the first time since the creation of Nazi Germany and Hitler’s rise to power, it’s possible to see the beginnings of a campaign based on a complete and utter lie.
If Trump and his people succeed, investigations will begin into this lie, and the mechanisms of the state will be used to (at the least) put Biden on the defensive for the entire duration of the campaign.
Based as it is on a series of utter falsehoods, this approach is so fundamentally anti-democratic that, if it were to succeed, there would be little hope left.
You just have to hope, watching it from a distance, that the American media will fight it tooth and nail, and that the American people won’t fall for it.
But as I write this, he’s claiming on Twitter that he’s “doing REALLY well, medically, on the Coronavirus situation (Plague!). It will happen!”
And people are congratulating him in their thousands.
Are the American people about to swallow Trump’s biggest lie yet?