According to Godwin’s Law, revealed online by the American lawyer and author Mike Godwin in 1990, the longer an internet discussion continues, the greater the likelihood that someone will be compared with Hitler. Another internet wit combined this with Moore’s Law on computer memory, and concluded that the length of Twitter threads which end with accusations of fascism, halve every year.

Well last week, Godwin’s Law reached a kind of singularity, as Godwin himself accused the Trump White House of behaving like fascists. It’s no longer a joke. Many people, not just keyboard warriors, believe that we are witnessing a creeping fascism in the West, and that it’s time to stop laughing about it and do something. At the very least, according to the Scottish Labour leader, Richard Leonard, Donald Trump's visit to the UK next month should be cancelled to show that he has stepped beyond the bounds of civilised behaviour.

Looking around the West last week it was hard to disagree that something nasty is on the creep. We had Trump locking up separated immigrant children in “concentration camps”. Images were fresh of the immigrant rescue ship Aquarius, laden with 630 migrants from Libya, being turned away from Italy and embarking on a desperate odyssey that ended in the Spanish port of Valencia.

Then we saw an Italian minister of the interior, Matteo Salvini, using the kind of language about Roma that echoed the Nazis attitude to the Jews. The Lega politician called for a “mass cleansing, street by street, neighbourhood by neighbourhood”. Far right parties have been elected in a swathe of Central European and Eastern countries from Turkey to Hungary. An anti-immigrant party won this month's election in Slovenia, confirming that small countries aren't immune to the march of the right. Far right Swedish Democrats are racing ahead in the Swedish polls before September’s elections.

You don’t have to subscribe to the “Brexit is fascist” hyperbole to be more than a little worried about what is happening to our political culture. Trump is something we haven’t seen in a developed country since the 1930s: a political leader who launches trade wars as a deliberate act of policy, alternately threatening and then sucking up to dictators like Kim Jong Un. His behaviour at global summits, such as the recent G7, where he snubbed the EU and picked a fight with Canada’s Justin Trudeau, was reminiscent of the delinquent nationalism of fascists like Benito Mussolini.

The state of global capitalism is also redolent of the 1930s. The 2008 crash brought the corrupt banking boom to an abrupt end, and, as before, the burden of resolving the crisis is being borne, not by the rich, but the relatively poor. Bankers carried on with business as usual after a state bailout: the top one per cent have seen their assets increase in value thanks to money printing; while wages have fallen in value. The Institute for Fiscal Studies confirmed last week that this is the longest pay freeze since the Napoleonic Wars. Ruling classes throughout history have been adept at diverting economic discontent onto outsider groups whether Jews, Muslims, Irish or Gypsies.

So, things are bad, there's no denying it. I’ve been knocking around politics for a good many years and can’t remember anything like this. Even the braying coarseness of Tory MPs following the SNP's walk out earlier this month was of a different kind: as if, in the age of Trump, restraint and magnanimity have gone out of fashion. However, we need to beware assuming that this new populism, is an exact replica of 1930s fascism.

Fascism was a romantic, pre-Enlightenment philosophy which glorified a master race and saw other peoples as genetically inferior. Nazism had a populist element: it was, after all, called the National Socialist Workers Party. But it was also militarist, expansionist and sought to enslave neighbouring states. Populists like the Five Star Movement, led by the comedian Beppo Grillo, which won the recent general election in Italy, are rather different. One of the “stars” is environmentalism - and yes, I know, Hitler was a vegetarian, but he certainly wasn’t green.

Trump is belligerent, certainly, and demonises immigrants, but he is not the leader of a two-million strong militia with ambitions to annex Canada and enslave Mexico. He has the National Rifle Association, but even they don’t strut around in jackboots, smashing Muslim businesses. At least not yet. Trump isn't so much fascism as flashism: a kind of celebrity populism which presents itself more like Dynasty than Der Sturmer. Trump doesn't study philosophers like Heidegger and Schopenhauer as Mussolini did. He doesn't have a concept of Der Wille or Das Volk – only his wealth and his folk.

This is no cause for complacency, however. As David Runciman argues in “How Democracy Ends”, assuming that military dictatorships are on the way may blind us to what is actually happening. We are seeing, rather, the subversion of democracy from within by political leaders who subscribe to democratic values and even claim to support minority rights. Vladimir Putin still stands in relatively free elections, but he has been busy skewing political perception through fake news and other post-modern dark arts, while his oligarch friends export Russia's wealth to the London property market.

Yes, the end result, world war, is certainly a possibility. Though again, as he demonstrated with his sudden detente with Kim, Trump has no ideological dimension. He doesn't think much beyond ego-gratification and what he calls the “art of the deal” - winning short term gains. But his headstrong abandonment of rules-based diplomacy and free trade could certainly provide the context for international conflict. You don't need jackboots to start a war – just blind self interest.

Which brings us to the Trump visit to the UK. There have been calls for it to be cancelled, and it is hard to disagree. He's been refused leave to address parliament, and has effectively been excluded from London. But actually refusing him admission to the UK would set an awkward precedent since, distasteful as it may be, he is still the elected leader of the United States. We have recently given actual state visits to genuine dictators like President Xi of China, whose regime incarcerates dissidents and executes more people annually than the rest of the world combined.

It would be best if Theresa May made clear through diplomatic channels that now might not be the right time – if ever. However, if the visit does go ahead, it should be used to make a very clear statement that he is not welcome. This should not include militant disruption and violence, along the lines planned by Antifa activists, because this would only strengthen Trump's popularity at home. As a flashist, drunk on celebrity, what Trump really can't cope with is ridicule. If he ventures to Scotland to play golf, he should be met by a carnival of contempt, led by that six metre high balloon of the “orange baby”, and an immigrant march across his golf links. Let's not dignify Donald Trump as some ideological tyrant, but portray him as he is: an international buffoon, a confidence trickster and liar, who has duped his country, and turned the greatest military power on the planet into the laughing stock of the world.