In the immediate aftermath of 9/11, the satirical newspaper The Onion illustrated its front page with a haunting image. Photoshopped together were a selection of American celebrities: Michael Jackson waving to his fans, Tom Cruise guffawing at a joke, Britney Spears dancing semi-naked with a python. And above the image was the following headline.
"A Shattered Nation," it read, "Longs to Care About Stupid Bull---- Again."
In recent weeks, that particular form of longing has once again become unmistakable – not only in America, but across the Western world. Which is why, on Sunday night, I think Will Smith performed a valuable public service. At a time of war, geopolitical disarray and fears of nuclear armageddon, he heroically enabled millions of people to focus instead on something utterly meaningless and immaterial.
God bless him for providing this respite from the terror of reality. Forget stripping the man of his Oscar. The President should award him the Medal of Honour.
But, while it's no doubt doing us all good to obsess for days on end over this spectacular non-story, it does carry a potential risk. Which is that we'll draw some kind of sanctimonious moral lesson from it.
The incident began when Chris Rock, the comedian, made a joke about the appearance of Jada Pinkett Smith, Will Smith's wife. And so, even if people deplore the violence of Smith's response, they may conclude that it's wrong to joke about the way someone looks – and that therefore, we should never do it.
I strongly disagree. Joking about the way someone looks is a perfectly legitimate element of comedy. And to make it taboo would be an absurd overreaction.
That's not to say I think Rock's joke about Jada Pinkett Smith was funny. I don't. He joked about her having no hair. But the reason she has no hair is that she suffers from alopecia. Which she can hardly help.
There are times, though, when jokes about a public figure's appearance are valid, and even useful. For 10 years I was The Telegraph's parliamentary sketchwriter. And a sketch, at heart, is a cartoon in verbal form. So sketchwriters tend to describe politicians in a cartoonish way: exaggerating their most prominent features, the way cartoonists do.
The reason, however, is not to pass comment on a politician's physical attractiveness, or lack thereof. Any reference to his or her appearance should always have a point to it. It should tell us something about his or her character, persona, behaviour or mood.
If, for example, you write that Boris Johnson looks like a Dulux dog peeping out from under an upturned colander of spaghetti, you're suggesting something about his character: his chaotic unpredictability, and his habit of getting himself into trouble (and also of getting away with it, because, as with a big, cuddly sheepdog, people just can't help forgiving him).
Equally, if you write that Nigel Farage has a bug-eyed smirk that makes him look like a toad plotting a practical joke, you're evoking a key aspect of his approach to politics: his wicked, even vindictive sense of mischief.
When Theresa May was prime minister, I often used to write about her appearance (although no more often than I wrote about David Cameron's). But when I wrote, for example, that she looked like someone forced to attend a fancy dress party at gunpoint, the aim was not to disparage her wardrobe. It was simply to note the improbable contrast between the joyful flamboyance of her clothing and the scowling severity of her character. So strong was this contrast that the former actively seemed to accentuate the latter. It made her appear all the more awkward and uncomfortable.
Similarly, John Crace, sketchwriter at The Guardian, used to call her "the Maybot". Partly this was about how she looked: cold, stiff, forbidding. But it was also about her performance as PM: ponderous, uncharismatic and prone to malfunction.
The all-time master of comic caricature, however, was not a sketchwriter but a TV critic. Clive James wrote that Barbara Cartland's eyes "looked like the corpses of two small crows that had crashed into a chalk cliff". He wrote that Rod Stewart's "very tight striped pants" made him look "like a bifurcated marrow". And, perhaps most memorably of all, he wrote that Arnold Schwarzenegger looked like "a brown condom stuffed with walnuts".
These physical descriptions are not kind, generous or sensitive. But they are stupendously funny. I don't know whether Clive James' mother ever told him that if he didn't have anything nice to say, he shouldn't say anything at all. But if she did, I'm glad he ignored her.