Although a dominant cultural force since the 1950s, American television only hit its true, glorious peak in the final decade of that century. Among the gems to introduce cinematic ambition, sweeping storylines and renegade perspective to the small screen was The Simpsons. Nominally a cartoon which began as a short on the fledgling Fox channel, it invited the country to at once laugh at its vanities and flaws and examine its familial and civic institutions with an affecting and caustic touch. The show was in its third season when, on September 26th, 1991, it broadcast Mr Lisa Goes To Washington, in which Lisa, the hyper-bright, idealistic daughter, earns her family a trip to the capital, where she will compete in the national finals of an essay contest on the theme of patriotism.As with many of those early-season episodes, the flecks of genius are to be found in the casual asides. The judges mark Lisa’s regional essay out of 10 under the categories of Clarity, Organisation and “Jingoism”. Outside the White House, the perpetual protesters reflect the sanguinity of the coming decade (the ’90s are now held up as some lost idyll), holding up placards reading “Things Are Fine”, “No Complaints Here”, “One Happy Camper”.Lisa Simpson from The Simpsons. But Lisa, on a dawn visit to the memorial of one of her heroines, stumbles on a secret meeting in which her local congressman takes a bribe from a lobbyist to permit the chopping down of the Springfield forest. In tears, she visits the Lincoln Memorial to seek counsel – “Honest Abe, he’ll show me the way” – only to find it crowded with other citizens pestering the great man with their own petty concerns. Disillusioned, she rips up her essay entry and scandalises both Homer and Washington’s political set by reading aloud- in the Kennedy Centre- an accusatory polemic titled “Cesspool on the Potomac”.That half-hour of television, aired a quarter of a century ago, remains a deft reflection of the nagging sense that in US politics, the themes and scandals never really change, only the names and faces. Summer in Washington thickens into a syrupy and bug-laden haze. Walking is reduced to snail’s pace along the National Mall, where visitors take photographs in front of the monuments and then refuge in the cool of the museums. For the past month, the state of the reflecting pool, directly in front of the Lincoln Memorial, has been held up by Trump’s critics as an apt symbol of a befouled presidency. The administration’s commissioned upgrade, painting the pool’s base an “American-flag blue”, had promised a lagoon of crystal clarity. It briefly was. But over the past month, the water became discoloured with heavy algae, clumps of the blue sealing paint and even dead ducklings, rendering the place a calamity. Algae in the newly renovated Lincoln Memorial reflecting pool in Washington. Photograph: EPA Trump has blamed criminal vandalism for the despoiling. The commentariat and Democrats have labelled it a perfect metaphor and in keeping with other disastrous vanity projects: the travesty of the UFC night at the White House; the East Wing a rubble-strewn building site; the Kennedy Center nameplate covered in tarpaulin and operating a zombie programme; the desolate sight of Trump’s Great American State Fair, which has attracted a cruel lack of interest from the general public, leaving Fox News hosts, broadcasting on site, suffering the humiliation of claiming the venue was crowded even though the screen showed an empty fairground. From the left, the laughter and taunting have been ceaseless, deepening Trump’s paranoia that the mainstream media is incapable of fair reporting. He could point to other renewal projects in the city, such as the Columbus fountain outside Union Station and the cascades at Meridian Hill, which are both sparkling and working now for the first time in many years.But through ineptitude and catastrophic timing, the reflecting pool will be fenced off as Americans consider who they are and what their country means 250 years into the grand experiment.Fencing and signs advertising the upcoming events celebrating the nation’s 250th anniversary block visitors from the Lincoln Memorial Reflecting Pool in Washington. Photograph: The New York Times