It resembled the final, triumphal, scene in every American high-school film you ever saw. You know the one, where the least fancied girl becomes "prom queen", and swirls off into the distance with the hunkiest, handsomest member of the football team. Well, it happened to Michelle Obama on Monday night, except that her audience was the American viewing and voting public, and the stakes were the highest they could possibly be.
Hair-perfect, dress-perfect, word-perfect, every inch the valedictorian, Mrs Obama was campaigning to be First Lady (and not to let her husband down). She acquitted herself magnificently. There was not a doubt that had been raised about her – and by implication about her husband – that she did not identify, only to knock squarely on the head.
Her tendency to Chicago Southside lippiness? She knew exactly what was required of her and spoke in that peculiarly American tone of feisty demureness that convinces everyone and threatens no one. The black family an issue? Well, there she was speaking lovingly of her husband, Barack, and showing off their two winsome daughters. And those nagging little doubts about her patriotism? Absolutely no worries there. She was as down-home as Dolly Parton and as sound on shared values as any small-town preacher. She even had a kind word for the Hillary crowd: people like Mrs Clinton, she said, had cracked the glass ceiling "so that our daughters – and sons – can dream a little bigger and aim a little higher".
All in all, Michelle Obama did more than enough to remove race – there, the word has finally slipped out – from this year's electoral considerations. Or she would have done, if race had ever been a consideration, which vast numbers of Democrats and potential Democratic voters would vehemently deny. An increasingly colour-blind America, they would insist, is ready for a black President.
Well, I'm sorry to spoil the party in Denver, but I don't believe them. Race is a problem for the Obamas, however model their all-American family, and it will be a problem until the last voter pulls the lever on his or her vote on 4 November. To cast a vote for Obama when the competition is a white woman encumbered by surplus Clinton baggage is one thing. To vote for him when the alternative is a white male of impeccable patriotic credentials and the prize is the White House is quite another.
For all the – justified – boasts about the proverbial American "melting pot", and recent forecasts that the US will have a non-white majority by 2040, one type of racism remains an insidious fact of American life: the divide between white and black. It looks less forbidding at the very top – think Condoleezza Rice and Colin Powell – and less conspicuous at the very bottom. But right in the middle of the white middle class, an assumed superiority runs so deep it hardly needs to be articulated.
That it is less in evidence in the wake of the civil rights movement and affirmative action does not mean that it no longer exists. Its silent invisibility is what makes it so dangerous to Mr Obama's presidential prospects. As with French supporters of the far-right National Front, Americans have learnt to keep their deepest prejudices to themselves. And the pollsters, however sophisticated their techniques, may never gauge the half of it.
It is often said that Washington DC is the exception rather than the rule, as a one-industry politics and government city. In many ways, though, it is more typical of the rest of the United States than New York City, San Francisco, Miami or other places more often experienced by European tourists. As a visitor, you will see barely one third of the city – the official part, the part that is white and the part that is a bit mixed. The rest of Washington, like the rest of many US cities, is black. Everyone who lives in and around Washington – as I did for five years – soon learns, to the yard, where the "frontline" runs, where white people do not live, where their children do not go to school, and where to lock the car doors and run a red light rather than linger.
In the city centre, the pavements, like the shops, offices and transport, can be minor fields of hostile racial encounters, facing-down and "dissing". Black America senses white condescension and entitlement a mile off. Nothing any European city offers in the way of day-to-day racial tension can compare. And, if you stop to observe, you can understand why. From their posture, to their refused eye-contact, to their commanding tone, educated white Americans all too often exude something more visceral than just a presumed intellectual superiority.
In urban areas, what is more, they have increasingly arranged their lives so that – outside work – their paths rarely cross those of black Americans. Not only do they live in separate parts of town, shop in separate malls and worship in separate churches. They also use quite separate road systems, bypassing undesirable parts of town.
One of my most embarrassing experiences was offering to share my taxi with an elderly (white) couple, if they were going the same way. It was at Baltimore airport, the queue was long; they were near the back and I was near the front. But no sooner were we in the cab, than the woman demanded an enormous detour to avoid the direct route into "white" north-west Washington through "black" north-east. The (black) driver was happy to go direct, the rest of the journey passed in frigid silence, punctuated by whispered racist remarks between the couple – about me!
Now you can argue that my experiences of living in, rather than visiting, the US go back five years or more, and that a rising generation of Americans has fewer hang-ups about race, religion or anything else. James Zogby is just one US pollster who discerns a sharp change of attitude among Americans under 35 or thereabouts. This view, according to which younger Americans are more widely travelled, more widely read and more broadminded than many of their elders, may indeed be correct, and it offers hope that the rift between black and white may be overcome.
Whether there are yet enough colour-blind Americans to elect Barack Obama President, however, must still be open to question. For all the excitement generated by his campaign, it is not only in Europe where older people are more likely to vote. And even the colour-blind might feel that less than a single term in the US Senate is not quite enough experience for the Oval Office. So when Michelle Obama told the Democratic Convention that Mrs Clinton and others like her had helped crack the glass ceiling so that the next generation could "dream a little bigger and aim a little higher", she might unwittingly have been foretelling her husband's destiny, too.
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