From a distance, it looks bold and bright, like the very stars and stripes it is representing, an ideal as much as a flag. But come closer and you’ll notice how pockmarked and scarred its surface is, full of mysterious holes as if nibbled by cockroaches. Could there be a more fitting symbol of America right now? The British Museum has marked the United States’ big vote by announcing its acquisition of Flags I, the screenprint by Jasper Johns that is said to be worth millions. Three years ago, the London venue put this image on the posters and catalogue for an exhibition called The American Dream. That title sounds almost quaint today. Who, at the close of Donald Trump’s first term in the White House, can now utter that phrase without irony? American Dream? Can those words really apply, given that the arrival of this election has been marked by shops and businesses being boarded up, and with Trump making bizarre remarks challenging the sanctity of the poll, threatening the entire democratic process? What makes Johns’ American flag so perfect for this charged, climactic moment? Well, this is an anxious image of the nation fraying. But to fully understand this work, you need to follow Johns’ very personal interpretations of the flag over nearly 70 years. Johns is not an overtly political artist. He’s reticent about every aspect of his art and life. In the 1950s he, Robert Rauschenberg and Cy Twombly formed both an art movement and a love triangle. They all broke with the austere sublimity of abstract expressionism to incorporate real life in their creations – from Rauschenberg mixing photographs, paint and stuffed animals in his Combines, to Twombly spattering enigmatic graffiti on to canvas. But the breakthrough for this new approach, to art and to life, came when Johns made his first US flag in 1954-55. Simply called Flag, and owned by New York’s MoMA, it is made of a layer of collage covered with a much thicker piling-up of encaustic paint that produces an enduring, almost rubbery surface. It gives Flag a solid feel, more like a sculpture than a painting. But what does it say about the actual US flag? Everything. Nothing. Through the colours, you can make out fragments of newspaper headlines in the collage below. They don’t add up to any readable narrative but instead imply complexity and mystery. Johns made this Flag at the very centre of the 20th century, which has been called The American Century, given the country’s rise and increasing global influence during those 100 years. But no one has ever mistaken the work for a simple patriotic banner. It’s never going to be held sacred by conservatives or flaunted by crazed militias. Why is that? There is a distancing, a questioning, in it. Johns said simply that he dreamed of the flag so he made a flag. He never said what kind of dream. This unwaveable flag, frozen in wax, full of hints of stories, invites you to stand back, to contemplate it coolly. It is a flag in quotation marks. Johns has shrunken America itself to something on a wall. But his irony is not cold. It’s moving. What he does is to shift the meaning of patriotism. Instead of a brash icon, this Flag has become a great American novel or a song on the radio played on the lost highway. That poetry becomes still more haunting in White Flag, from 1955, which strips out the famous colours to leave a pale spectre, like a civil war ghost. It’s a bit blunt, but also true, to say that Johns – as a young gay man in socially conservative 50s America – was finding his own patriotism, his own country. But by the time he created Flags I, the print now in the British Museum, a lot had changed. It was 1973. Johns was rich and famous. The 60s had been and gone. The realm of public life was starting to darken, as it has in our century. Flags I was created the year after the Watergate affair began. The cracks and damage to the stars and stripes are, surely, the marks of national shame and fury after this revelation of conspiracy and corruption at the heart of government. From our historical moment, the rise and fall of President Richard Nixon looks like a modest dress rehearsal for Trump’s assault on democratic norms. Nixon had mobilised what he called a conservative “silent majority” against the perceived dangers of Vietnam war protests. Trump openly praises his supporters for apparently trying to run Joe Biden’s bus off the road. But you can’t reduce Johns to any simple “message”. He is interested in complexity. The whole point of his art is to take a simple found image or thing – a target, a map, a beer can, the flag – and remake it in a subtle, elusive way. The British Museum’s new addition is a riposte to the delight in bold icons taken by such pop artists as Andy Warhol and Roy Lichtenstein. It was Johns’ first attempt at screenprinting, which they loved. Johns thought it a “simple-minded” technique. But he learned from Japanese printmakers how to make a multi-layered, sophisticated version that subverted the Warholian clarity of the method. He gleefully said the result, Flags I, “might properly be considered an abuse of the medium”. It takes pop printmaking into unfathomable layers of technical finesse. Complexity. Nuance. Ambiguity. None of these are very Trumpian concepts. But neither does Johns satisfy anyone’s anti-American sentiment. He has explored what the US flag means more thoroughly than any artist. He’s revealed that it is much more than a coarse political symbol. Officially selected as the republic’s flag back in 1777, in the age of Washington and Hamilton, the Stars and Stripes is loaded with the emotions of generations. It was draped on Lincoln’s funeral train, raised at Iwo Jima, Ground Zero and even on the moon, as well as being flown in every song by Bruce Springsteen. Yes, there’s plenty of bad stuff, too. But, since he made that first Flag, as a bohemian outsider in postwar America, Johns has been showing – in his gentle, witty, lyrical way – that everyone owns a bit of this flag. It is not the property of bigots. It is not even the exclusive property of Americans. Much of the world is hoping that, after this election, our dreams, too, can inhabit the Stars and Stripes again.