The Wizard of Oz is such a classic film that I don’t remember the first time I saw it. It seemed to be on TV every Christmas during my childhood and became a part of my cultural education, a formative film language. A new study claims the film, which went through a staggering run of directors, writers, songwriters and script edits during its production, is the most influential film ever. I don’t know about that, but I frequently rewatch it to study how great film-making can make any story fly like a wicked witch’s monkey.

Judy Garland’s performance as Dorothy is a wonder of innocence, sensitivity and determination. At the start of the film, she wonders what lies over the rainbow and then, in a concussed dream, enters the rainbow. The combination of imaginative anything-is-possible scale and picaresque narrative style is totally cohesive, so that what could have been a discordant riot of songs, set pieces, production design, acting styles and plot somehow barrel along together, from the special effects of the tornado scenes to the twinkling transformation into Technicolor, to the sinister and deliberately fake-looking malachite-green art-deco sets of Emerald City. Then there’s the surging music, in which every group song increases in volume and hysteria until there’s a kind of bullying mania to it.

Oz is first wondrous and revelatory, then sinister and suspect, a good trip that goes wrong, swerving from the vivid Ikea yellow of the munchkins’ brick road to the scorched red-and-black tableau of the wicked witch’s eyrie.

It’s this lurking inner wrongness, the darkness at its edges and the emptiness at its core, that speaks to me now. The US of The Wizard of Oz is not so far from the US of today. The supposedly great man living in Trump Tower – I mean Emerald City – turns out to be a con artist, a bloviating coward who relies on self-aggrandisement and empty shows of power to cow the people. The film’s chaotic momentum, in which events roll luridly from one rococo set-piece to the next, with Dorothy’s destination and the purpose of her trip moving in and out of focus, seems strangely familiar. And the central reveal about the hollowness, cynicism, opportunism, egotism and fakery of our leaders is chillingly apt.

L Frank Baum’s original novel was written in 1900 and the film was made in 1939. Yet all the themes of Trump’s America are there. We can read the catastrophic effects of climate change into the tornado that sets the narrative off, see the opioid crisis in the characters’ drugged sleep in Oz’s Powell and Pressburger-esque poppy field, and empathise with the mangy Lion, rusty Tin Man and understuffed Scarecrow’s search for organ donors and reliable medical support in an Oz without a solid welfare state.

Dorothy’s family life with her aunt and uncle in Kansas resembles Dorothea Lange photographs of rural poverty. Dorothy and her relatives are skinny, careworn, shabbily dressed, their house and outbuildings peeling. The monochrome scenes are in a washed-out grey, not a stylish noir. Dorothy is isolated. She has no friends her own age and does not meet other children on her adventure.

FBI finds stolen ruby slippers from Wizard of Oz after 13 years Read more

Despite the munchkins’ evident civic pride, the values of Oz are not much different from those of Kansas in 1900 or 1939 or 2018. Yes, the Wicked Witch of the West has all the best lines and the chewiest performance, by Margaret Hamilton, but the film revels in the violent deaths of “ugly” women, who have houses dumped on them or drown in water that melts them like acid, while the greatest deceiver, the Wizard, simply shrugs and floats away at the end of the film.

Offstage, Garland was harassed and bullied by directors and male co-stars, while there were painfully few women (including editor Blanche Sewell, writer Florence Ryerson and a song lyricist) among the dozens of behind-the-scenes contributors.

The Wizard of Oz was released just months into the second world war, as increasing pan-European fascistic nationalism, racism and antisemitism, authoritarianism and social division culminated in six years of genocidal violence and bloodshed, with millions dead and millions having fled. I’m not saying we’re on the brink of a third world war, but why am I reading these messages into this film, at this moment? The memorable part of Dorothy’s last scene in the Emerald City is not the revelation that her enchanted shoes can carry her home, but the ashy pall of disillusionment and disgust following the unmasking of the false saviour, the Wizard of Oz.

Then there’s the perturbation of watching Dorothy wake up in her own home, where the tiny local population colludes with her in a wholesale rejection of the world of Oz in favour of keeping to one’s own backyard.

The Wizard of Oz is a truly American narrative, and more influential than ever: Dorothy goes from wishing to explore all the shades of the rainbow to gratefully embracing black and white, from reaching out to defiant insularity, from exciting new friends to old stalwarts. Perhaps, if the filmmakers had switched back to Technicolor at that moment, we might hear the Wizard’s last triumphant bellow, and see a bright red Make America Great Again hat in a corner of the room.

• Bidisha is a journalist and author