Over the past few weeks, a random kaleidoscope of images has been flashing through my head. Some are characters from movies not seen since childhood. Others are snippets from literature or iconic art. What joins them all is an exaggerated, almost kitschy evil.

These images seem to be standing in for the real carnage my brain is trying to process: the bodies pulled from the rubble in Gaza, a school full of young pupils blown apart in Iran. The more than 1 million people in southern Lebanon expelled en masse from their homes. (Alex in the film of A Clockwork Orange appears, eyes clamped open as liquid is dripped into them, unable to blink away what is scorching his vision.)

What is so bewildering about the cruelty is how it has been allowed to pass, its casualness. Donald Trump hovers above the circus of death and chaos. (Billy, the clown-faced puppet in Saw, pops up rasping, “I want to play a game”.) Trump defies attempts to make his actions cohere with any particular strategy. His wars, killing of innocents, and indeed, the threatening of entire civilisations are reshaping the world, but without him even having orchestrated some master plan. He is animated by little more than momentary impulses and resentments.

Trump’s seeming lack of vision or ideology are misread as attributes that make him somehow less dangerous than the authoritarians of the past who have become the template for what evil looks like. Take the debate over whether Trump can be described as “fascist”. “You can’t be a fascist,” said the Wall Street Journal’s Barton Swaim, “without in any way meaning to be one.” Trump is inept, inconsistent, “puzzling and exasperating”, but not a fascist, he claims.

Trump also does not adhere to the style or affect of the fascist model: he doesn’t hold rallies, wear uniforms or make fiery speeches from balconies to flag-waving throngs. He hasn’t (entirely yet) overturned the constitution and dismantled democracy. He is an addled comic figure, a man whose very soul is bared in his angry outbursts on social media or in rambling speeches without self-awareness or self-consciousness. He talks about the war on Iran flanked by a gigantic Easter bunny, posts an image of himself as Jesus. He “always chickens out”. (A Wheeler from 1985’s dark fantasy Return to Oz: screeching, giggling, chasing, then wincing and withdrawing when its quarry strikes back.)

But isn’t this what evil is? A projection on to the world not of overbearing and large intent, but smallness and fear? The consequences of violence are secondary to the validation that comes from inflicting it. Trump’s constant self-aggrandisement, his grudges against political adversaries, the fury at being challenged by the press, the revenge he promises to wreak on the Iranian regime. All are ways to erase and avoid what is a permanent terror of humiliation and obsolescence. (Goya’s Saturn, wild-eyed, devours his son.)

It is in that very puniness that insatiable evil lies. In 1931, after Adolf Hitler’s Nazi party had surged in the polls, he was interviewed by the US reporter Dorothy Thompson for Cosmopolitan. “When I walked into Adolf Hitler’s salon in the Kaiserhof hotel,” Thompson recalled, “I was convinced that I was meeting the future dictator of Germany. In something like 50 seconds, I was quite sure he was not. It took just about that time to measure the startling insignificance of this man who has set the world agog.”

“Think of Benito Mussolini,” wrote the journalist Barbara Grizzuti Harrison in the LA Times, “jackbooted, lantern-jawed, squeakily bombastic, posturing from the little balcony of his office on Piazza Venezia in Rome – that remarkably dopey stiff-armed Fascist salute, the absurd oratory. Think of that funny man, that consummate buffoon”, and remember that “just because something is silly doesn’t mean it isn’t dangerous”.

We tend to imbue history and all its grave events with a seriousness and coherence that we struggle to apply in the present. And I think that’s because it’s hard for the human brain to encounter evil in ludicrous form, and still recognise it as such. That’s how it creeps up on you. That’s why you ask how such crimes were allowed to happen in the past. The answer is that it rarely arrives with the intent and identifying hallmarks of a villain. It arrives in the form of broken people, whose power lies in their unquenchable desire to make themselves whole no matter the consequences. Alongside Trump’s absurdity sits the fact that he has access to the means of nuclear annihilation and a sociopathic appetite for escalation. (Milton – “better to reign in Hell than serve in Heaven”.)

Evil is composed of frivolity and nonchalance and fragility, as well as relentlessness and insatiability and brutality. Another recollection from my reel. In the movie franchise The Purge, the United States has passed a law that for 12 hours, all crime is legal, in order to purge grudges and blood-let the inherent darkness in all humans, so that the rest of the year can be free of crime. But it is not enough for the population that they ravage each other for a day. They also dress in elaborate costumes, wear gaudy makeup, fashion masks and blast music in a ritual of relish.

What the film gets at is that crime is not satisfying without the performance. Without the assertion that as you commit the gravest of sins, your power in doing so comes from approaching it trivially, with the privilege of play. It is not the act, but the licence. It is not enough that ICE separates families and uproots lives, it is important that the whole thing is rendered as celebration, with images of Trump standing next to alligators wearing ICE caps next to the line “Alligator Alcatraz” in movie poster font.

There is no cajoling or humouring of this sort of jubilant wickedness that will make Trump spare his quaking allies. No minimising of it as nothing ideological or without a strategic purpose, and therefore ultimately manageable. The unbridled cruelty and violence that he is unleashing and enabling domestically and abroad draws on all its precedents, and can only be fiercely fought – and with urgency – or it will consume all. (Patrick Bateman, American Psycho: “My pain is constant and sharp and I do not hope for a better world for anyone. In fact, I want my pain to be inflicted on others. I want no one to escape.”)

• Nesrine Malik is a Guardian columnist