Matthew Norman: The peculiar tragedy of this flawed hero, John McCain

For one whose single rhetorical flourish is the gratingly incessant appellation "My friends", John McCain has very few left. The roll call shrinks by the day as his bamboozled campaign grows nastier, and if the decline maintains its trajectory this year's Friends of McCain Thanksgiving Dinner in Arizona will be held, in homage to his naval career, in a solo canoe. By then, even the Clintons will have baled out because, barring a malevolent miracle, Barack Obama will be President-Elect, and Senator McCain's value to them as Oval Office seat-warmer until 2012 will have gone the way of Lehman Brothers. Even his wife, Cindy, can barely tolerate his presence, judging by the body language at the end of Tuesday's debate in St Louis. As they gingerly embraced, you sensed her wondering whether seven houses will provide a sufficient cordon sanitaire from each other's company come 5 November.

This debate was a riot of paradox, being at once both turgid and captivating, meaningless and hugely significant. As an aural event, it was tedious. Obama was much the more lucid, especially on healthcare and foreign policy regarding Pakistan, but McCain held his own on the economy (or about as well as any candidate advocating $300bn in tax breaks for large corporations and their CEOs could expect to do at this point in US fiscal history).

It was visually that this debate really mattered and, while it is too soon to divine public reaction from the polls, one suspects it went a fair way to securing Obama the White House in the absence of monstrous scandal: Barack and Britney caught in flagrante delicto at an Osama bin Laden fundraiser perhaps; Michelle giving OJ Simpson the Black Power salute on visiting day at the penitentiary; Russia unilaterally reviving the Warsaw Pact; or the detonation of a radioactive device on Pennsylvania Avenue.

McCain looked simply dreadful. Sallow, fatigued, hunched, tentative and miserable, this bulbous oblong of coiled rage came across as what the Prince of Wales knows as an appalling old waxwork. The clinching image, I think, was the rear overhead shot, as he made staccato movements across the stage that highlighted the large circle of hairlessness on his head. No bald man has won a general election in Britain or the US in the television age (Dwight Eisenhower was the last Anglo-American alopecian victor back in 1956) and this one is now a very long shot to buck the trend.

So much for this one, and on to "that one"... the most memorable moment of the debate season thus far. Flailing about idiotically in the quest to portray Obama as the Bush-Cheney cheerleader in contrast to his maverick self, Senator McCain mentioned an energy bill that emerged from the White House. "You know who voted for it? You might never know," he said, and then, without turning to face Obama, he flipped an arm in the younger man's direction. "That one," he added, lest any doubt remain.

We could argue until Doomsday whether "that one" was a rung or two down the offensiveness ladder from "uppity". My feeling is that it falls into that vast category of Things White People Don't Think Are Remotely Racist But Wouldn't Say In A Million Years About Other White People. Certainly, you can't imagine McCain using it of Hillary Clinton or Joe Biden.

But racism, while still a small, nagging threat to Obama's chances, is a red herring here. What was so revealing about "that one" was that it crystallised the uncontainable disdain that is annihilating McCain's reputation. It isn't undermining his candidacy, because the economic mayhem and his volatile reaction to it has already done that. Yet his inability to show Obama common courtesy is unveiling him to a previously admiring electorate as a mean-spirited, cantankerous old git. If the repeated use of "old" appears ageist, so be it. Everything about McCain's dismissive attitude to Obama is geriatric. In fact he is only 72, which these days is anything but old. My father is McCain's senior by a year or two, and could pass for his son. I have friends in their mid-80s whom I think of as contemporaries because there is nothing remotely retrograde about their perspective on life.

For all his energy, on the other hand, McCain could pass for 92 because he radiates the sourness of the crotchety Meldrovian grump, slumped in a high-backed, plastic chair snarling "dunno they're born" whenever a middle-aged politician appears on the telly. Everything about his debate demeanour bespeaks a man struggling mightily to subjugate his rage that, after all he gave up in the Hanoi Hilton – his freedom, health and, as seems increasingly evident, a portion of his sanity – this smartarse liberal from Chicago swans along, not yet out of his congressional diapers, to steal the prize to which he believes his sacrifice entitles him.

So while Obama vaguely but empathetically seeks to assuage the terrors of Americans about their financial future, McCain seeks sanctuary in the distant past. He unleashes the increasingly gruesome Sarah Palin, Alaska's very own Cretina D'Evil, to raise Obama's extremely tenuous links to William Ayers, a Weatherman four decades ago, and the only people listening are the rednecks at her rallies whose shouts of "Terrorist!" and "Kill him!" she is content to let pass without rebuke. McCain's flirtation with revisiting Tony Rezko, the bent Chicago property developer from whom Obama bought a chunk of land in a deal he long ago called "boneheaded", seems set to become a full-blown affair, meanwhile, and it can't be long before his surrogates dredge up the Rev Jeremiah Wright.

Like many failing generals, McCain is waging not the present war but the last one in which Field-Marshal Rove defeated John Kerry. He wants to shrink a truly Goliathan election into another Lilliputian one, a tactic as misconceived as making the race about mature and dependable character when it is so obvious that the only grown-up in the room is Obama.

What made McCain look so weak and hopeless on Tuesday wasn't just the combination of pallor, jerkiness, the tonsure and the contrast between how, when not speaking, Obama sat with commanding tranquillity, whereas McCain paced anxiously in the background like someone in a hurry who cannot remember where he parked the car. It was the image he projected of a man weighed down and constricted by the sense that the campaign he is fighting is unworthy of him, but unable to change his tune because there's nothing left to sing except "For God's sake don't trust this terrorist-consorting, America-hating naif."

It is the tragic hero's traditional fate to be brought down by a central flaw he cannot see in himself. The peculiar tragedy of McCain, a hero himself as his pandering to veterans ever reminds us, is that he well knows he is squandering his long-husbanded capital of personal decency with the sort of wild profligacy that created the economic catastrophe that should cost him the election. His entire sense of purpose and self-worth is founded on a romantic notion, bred in the bone of this son and grandson of admirals, of noble service to his country. This loss of his honour may prove more excruciating than losing the White House to a man that a year ago John McCain would never have dreamt of dismissing, with such vinegary condescension, as "That One".