"Forgotten but not gone" was the way in which the supremo of Boston politics, Billy Bulger, liked to dismiss the human irritants he had crushed beneath his trim boot. The same could now be said for the hapless 43rd President of the United States as the daylight draws mercifully in on his reign of misfortune and calamity. How is he bearing up, one wonders, as the candidate from his own party treats him as the carrier of some sort of infectious political disease? How telling was it that the most impassioned moment in John McCain's performance in the final debate was when he declared: "I am not George Bush."

Where, O where are you, Dubya, as the action passes you by like a jet skirting dirty weather? Are you roaming the lonely corridors of the White House in search of a friendly shoulder around which to clap your affable arm? Are you sweating it out on the treadmill, hurt and confused as to why the man everyone wanted to have a beer (or Coke) with, who swept to re-election four years ago, has been downgraded to all-time loser in presidential history, stuck there in the bush leagues along with the likes of James Buchanan and Warren Harding? Or are you whacking brush in Crawford, where the locals now make a point of telling visitors that George W never really was from hereabouts anyroad.

Whatever else his legacy, the man who called himself "the decider" has left some gripping history. The last eight years have been so rich in epic imperial hubris that it would take a reborn Gibbon to do justice to the fall. It should be said right away that amid the landscape of smoking craters there are one or two sprigs of decency that have been planted: record amounts of financial help given to Aids-blighted countries of Africa; immigration reform that would have offered an amnesty to illegals and given them a secure path to citizenship, had not those efforts hit the reef of intransigence in Bush's own party. And no one can argue with the fact that since 9/11 the United States has not been attacked on its home territory by jihadi terrorists; though whether or not that security is more illusory than real is, to put it mildly, open to debate.

Bet against that there is the matter of hundreds of thousands of Iraqi civilian casualties, more than 4,000 American troops dead, many times that gravely injured, not to mention the puncture wounds and mutilations inflicted on internationally agreed standards of humane conduct for prisoners - and on the protection of domestic liberties enshrined in the American constitution. If the Statue of Liberty were alive, she would be weeping tears of blood.

If Bush himself has been largely kept out of sight, his baleful legacy has been visible in the McCain campaign. McCain has made much of his credentials for independence of mind, a claim which once was credible given his support for immigration reform and opposition to Bush's tax cuts. But somewhere along the road to the Republican nomination, all of this became less important than the lessons of the Reagan-Bush-Rove political playbook which, with the exception of the Clinton election of 1992, seemed to have a track record of unbroken success.

McCain knew this from bitter personal experience, having been on the receiving end of Bush lowball politics in the South Carolina primary in 2000. Coming out of a convincing win against George Bush in New Hampshire he was stopped in his tracks by a smear campaign conducted through push-poll phone calls in which people were asked whether they knew that the daughter McCain had adopted from Sri Lanka was in fact the illegitimate child of an affair with a woman of colour. Now you would think McCain could never reconcile himself to a politician capable of those kinds of tactics. But there he was in the campaign of 2004, stumping the country for the incumbent, ingratiating himself with the conservative base he knew he would need, even as his old Vietnam buddy, John Kerry, was being coated in slime by the Swift Boaters.

Whatever misgivings McCain might have had about adopting the hardball tactics of his 2000 adversary have long since disappeared before the blandishments of classic Bush-style operatives like Rick Davis and Stephen Schmidt. "Do you want to be pure, or do you want to win"? they must have asked right after the nomination. Ditching Joe Lieberman as a running mate and unleashing pitbull Palin was his answer.

So even while George Bush is kept at arm's length from the campaign, his campaign style lives on as Obama is stigmatised as a terrorist-friendly stealth-socialist, too deeply unAmerican to be let anywhere near the Oval Office. "He just doesn't see America as we do" says Sarah Palin trying to wink her way into Dick Cheney's seat. McCain is betting the house that this way of doing politics has at least one more hurrah left in it, and we will find out on in the early hours of Wednesday morning whether he is right.

The Bush presidency is the spectre haunting the feast in more than tactics. Although every conservative administration since Ronald Reagan has promised to deliver, through supply-side stimulation, economic growth without bloated deficits, they have never been vindicated in their blind faith in what Bush senior once rashly called "voodoo economics". Consistently, they have brought the US Wall Street crashes and recessions along with massive deficits; and yet somehow, the stake that history attempts to drive through the heart of their economic theology never puts the ghoul away.

No weight of evidence to the contrary has ever shaken the totemic belief that tax cuts can grow the economy robustly enough to compensate for drastic shortfalls in revenue. George W Bush clung to this belief even as the Clinton budget surplus was converted into a mountainous deficit, and John McCain continues to parrot the same belief with the shining face of a true believer.

Not even Gibbon could supply a story as fatefully bizarre as the ultimate consummation of Reagan-Bush conservatism, its last act: the most massive shift of financial power from the private to the public sector since the New Deal. Rather like the Pope deciding that all along he really wanted a barmitzvah.

If you look at this saga as the history of a dynasty; it's come full circle. For, believe it or not, there once was a time when Bush politics was about centrist moderation. Dubya's revered granddad, Prescott Sheldon Bush, son of an Ohio railroad executive and senator for Connecticut from 1952 to 1963, was punished in the Catholic towns of industrial Connecticut for his connection with Planned Parenthood. Not only that, but he was a trustee of the United Negro College Fund, the kind of institution that made the eventual career of Barack Obama conceivable.

But the Bushes have always been selective about idealism. And even at the height of the Kennedy-Johnson apogee, Prescott and George Herbert Walker Bush were turning the pages of Barry Goldwater's Conscience of a Conservative. They could smell the wind direction changing. The future of Republican money and Republican power lay elsewhere; with Texas oil. Hence the migration to Midland Texas of George Herbert Walker Bush and his makeover into a Texan who knew the ways of the corporate world; and how to bring about the Great Cosiness between government and business that seemed like the perfect feedback loop: money to power, power to money; tax breaks for the corporations; donations to those who might command the heights.

This is the politics George W Bush inherited, and he has been its faithful disciple; to the point of purging it of any remaining traces of pragmatism. It is astounding to hear rightwing talkshow bloviators rant about the predicament of the Bush administration being caused by its failure to carry out the true conservative agenda. For there never has been and never will be a more doctrinally faithful instrument of the creed. Never mind the hanging chads of 2000, the Cheney-Bush administration seized the moment to bring on the Goldwater-Reagan Rapture in which government was once and for all got out of the way of business.

So it hasn't really been all George Bush's fault, the stupendous American fiasco. He came to power armed with an ideology that was about to crash and burn; that was, years before the present tumult, already fatally disconnected from historical reality. It was on his watch that American government needed reinventing. It was responsible government that was needed in Iraq and Afghanistan; government that was desperately needed in New Orleans after Katrina, while all George Bush could manage was a fly-by. It is government that this most anti-governmental of all American administrations is learning that is needed now to save the United States from a second Depression.

In his heart of hearts I actually think the shell-shocked Dubya, somewhere in the bowels of his presidency knows this. But he is nowhere to be found, and so on goes the mad rant that health care reform and progressive taxes are the Trojan horse for socialist revolution. To which those who have another view altogether might want to say, fear not, for yours, as a Republican president once said, is a government of the people, by the people. And really it will not perish from the earth.