As we gloomily maintain the deathbed vigil for a Government whose end cannot come soon enough, it is the opposite end of the life-cycle that fixates US politics. Fittingly enough, on the eve of the nine-month anniversary of Barack Obama's election, America obsesses about the President's birth, and specifically his birthplace.

The gestation period for any conspiracy theory is far longer than that for human infants, of course, or even elephants. It tends, in fact, to be endless. It is 45 years since JFK was murdered, 40 since the first moon walk, and almost eight since the Twin Towers fell, and while the various notions (second gunman, studio mock-up, Mossad plot) were conceived almost immediately after those events, they have yet to deliver anything more substantial than lovingly nurtured insanity.

That rag-tag coalition of shock jocks, publicity hungry attorneys, the credulous and simple-minded, plain nutters and above all frustrated racists collectively known as "the birthers" have spent a year banging on about Mr Obama's arrival in this world, and their successors will be banging on about it long after he's left it for the next.

With the hissing wrath of those struggling ferociously to repress the volcanic pressure to screech "uppity nigger" at their head of state, these people conveniently conclude that Obama isn't their head of state at all. The second article of the US Constitution dictates that "no person except a natural born citizen" can be president, and the birthers argue that since Mr Obama was born in Mombasa, Kenya, he is disqualified.

One army officer, a Major Stefan Cook, refuses to serve in Afghanistan on the grounds that, since Obama isn't rightfully his commander-in-chief, the order to deploy is illegal. As for his lawyer, if you thought Esther Rantzen cuts an unconventional figure on the national political stage, here's a bottle blonde to make the old turnip-botherer look like Geoffrey Howe. Her sobriquet is Queen Bee of Birferstan, and the on-screen mini-biog accompanying a recent appearance on CNN briefly imbued that sober channel with Springeresque exoticism. "Dr Orly Taitz," it ran. "CA Attorney. Dentist. Real estate broker." As the sublime Jon Stewart pointed out, if you're contemplating a scam whereby a lawyer wins you enough in damages for botched root canal work to buy the home of your dreams, here's your gal.

Were it just Orly, whose legal qualification was earned over the internet, and a smattering of fellow narcissist-fantasists, the whole thing might be dismissed as touching idiocy. After all, if people wish to think that the August 1961 certificate of live birth is a forgery despite verification from Hawaiian officials, the state's Republican Governor and independent body factcheck.org; if they want to believe that birth announcements were planted in local Honolulu papers solely to prepare the ground for the day he could illegally enter the US and start his Islamist sleeper march on the White House; if they choose to trust a carefully edited interview with his Kenyan step-grandmother, cut off before she repeatedly confirms that he was born in Hawaii... well, that's their absolute right. Many of us solemnly believe objective absurdities. I believe that Tottenham Hotspur is one of the world's great football clubs, for instance, while a late relative was unswervingly convinced, as recently as 1989, that Hitler was working as a porter at a block of service flats in St John's Wood. Which of us is without a meshugas?

What is more intriguing about the birther "movement" – even than Orly's professional range – is the light it casts on the necrotic state of the American right. Concerns that the Grand Old Party would respond to Obama's near landslide by aping the post-1997 Tories, and adhering to the Tebbitian doctrine that the only mistake was in not being nasty and insular enough, prove naïve. The Republicans now make the Tories at their dog-whistling absolute worst seem achingly inclusive.

Who leads them at the minute is a mystery. Some think it's Sarah Palin, others the deliriously repugnant Rush Limbaugh, who inevitably joins the other oracles of US radio and TV in keeping the birther debate bubbling. What leadership there is, so it seems to this ignorant observer across the ocean, comes from the grass roots ... the sort of God fearin', gun-totin', sister-shaggin' sweethearts who screeched "terrorist" and "kill him" when John McCain mentioned Obama on the stump. Unable to compute that America elected a black man, they have decided that he isn't their President at all. No longer can they use the "n" word or fantasise publicly about lynch mobs. But they can divert their rage into a bogus legalistic dispute, rejected time and again by the Supreme Court, as freely as they like.

And their elected representatives follow them in dumb terror. A Huffington Post reporter approached a clutch of Republican congressmen on Capitol Hill this week to ask if they think Obama was born on US soil. Several scurried away, one at a trot, without replying. Another spent 20 minutes pretending to examine CDs in a shop to avoid the question. The only one prepared to answer said that Obama was a natural born citizen "so far as I'm aware" – an echo of Hillary Clinton doing her genteel bit to foster the myth about him being a Muslim sleeper during the primaries by referring to him as a Christian "so far as I know".

As Obama suggested after the arrest of the esteemed Harvard professor Skip Gates in his own Washington home, his election was not the magical cure-all some hoped. But then racism is stubbornly resistant to silver bullets. I was in Sydney on the day of the 400m women's Olympic final, and the Australian media was hyperventilating at the prospect of a Kathy Freeman victory healing all the wounds with the Aborigine people. She duly won her gold, and we left Olympic Park drunk on utopian dreams. The next day a colleague of Indian birth related how, outside the stadium that night, the first six empty cabs ignored his hails. The seventh also drove past before reversing. "Sorry, mate, couldn't make you out properly in the rain," the driver apologised as he beckoned him in. "I reckoned you was an Abbo."

These things take time. How much is anyone's guess, but America is waking to the realisation that untold millions aren't even close to accepting the democratic will that put a black man in the White House. The likes of Orly Taitz will parlay the issue into regular slots on Fox & Friends, countless more will kid themselves that their objection is constitutional rather than racial, and a few will be emboldened to hatch plots to uphold their patriotic ideals via an assassin's gun.

The Prez, meanwhile, is content to deal with such banalities as healthcare reform, and stay silent on the question of his birthplace. Politically speaking, this is a gift from heaven, exposing the vicious dementia of the Republican right to a degree of riducule that should help sweep him to a second term. The wider implications will please him less. But before we get too smug about British tolerance and racial maturity, perhaps it's worth acknowledging that, where the most senior elected black politician in American history is Barack Obama, ours remains Paul Boateng. All of us, it would seem, have a little way to go.