Where have we heard this tune before? Surely, Mr Mosley and his blackshirts had a right to march through the East End without being harassed and attacked by left-wing protesters? Surely, the fascists of Mussolini-era Italy and the Nazis in the crumbling Weimar Republic were expressing the sentiments of many by holding torchlight rallies, armed with knives and clubs, when, unjustifiably, they were violently opposed by Communists?

Sometimes, it’s too simplistic to argue that this is history repeating itself. Yes, the First Amendment to the US Constitution guaranteeing free speech applies to all, not just supporters of democracy.

But contrast the mealy-mouthed equivocation of US President Donald Trump with the declaration of one of his presidential predecessors, Jimmy Carter, in 1978, when swastika-carrying National Socialists planned a march through the Chicago suburb of Skokie, where one in six residents was a Holocaust survivor.

“I voice my complete solidarity with those citizens of Skokie and Chicago who will gather [on] Sunday in a peaceful demonstration of their abhorrence of Nazism,” was Carter’s response.

Is Trump a fascist? Not by the classic, traditional definitions of that term. But he is a populist demagogue in the manner of Huey Long, the Louisiana governor of the 1930s, and George Wallace, the Alabama segregationist of the 1960s.

His electoral appeal to the white nationalist right was delivered through blowhard rhetoric that sought to delegitimise his opponents. Many thought that, once in the White House, he would be reined in. He hasn’t been.

Many have seen Trump as a long-running joke that can’t bear much more repetition. But even the worst jokes have punchlines and those who oppose racism, Jews and non-Jews, have to hope his response to the Virginia violence is the punchline that turns the audience irrevocably against him.