If the weather forecasters are right, it promises to be another crisp and luminous autumn morning on the American east coast, just like that morning a year ago, when those four hijacked aircraft swept from an impossibly blue sky to kill 3,000 people and transform America and the world.

Some have argued that nothing has really changed. But those who doubt this proposition should consider this anniversary of September 11, a date that alone has become global shorthand for horror until then beyond human imagination, when that everyday tool of civilisation, the ordinary commercial jetliner, was turned against civilisation itself.

Today, of course, we pray nothing will happen. And if anything is attempted, at least precautions will be in hand. Although the FBI warnings have been, in the jargon, "non-specific", for the first time the colour-coded alert system created in March has been raised to orange. On that dreadful day 12 months ago, the fighter aircraft were too few and too late. Today they patrol the skies over Washington and New York. And yet fear is in the air.


A year on, that remains the greatest change, greater even than the huge hole in lower Manhattan where the World Trade Centre once stood, greater than the destruction of the Taleban regime. Greater even than the revelation of overwhelming American might, is America's realisation of its vulnerability.

This was the blessed land, separated from the world by oceans, watching with detachment the rest of the world that it never really needed to understand. International terrorism was for other people. Individual Americans might suffer from it, but only if they were "over there". Such complacency is gone, for ever.

Today Americans and the world remember September 11 2001. They will bow their heads in memory of unforgettable barbarity. But they will also remember individual and collective acts of bravery and generosity, by firefighters and police officers, as well as ordinary passengers aboard one of the planes who turned on their kidnappers, sacrificing their own lives to save the Capitol or the White House, and very probably hundreds of lives.

Will it be mawkish and overdone? Perhaps, at least for we world-weary Europeans. We will smile our condescending smiles at the dispensing of grief counselling, the endless public yearning for "closure".

As always, American sentimentality and patriotism are inviting targets for scorn, never more so than at a moment when American suffering seems to have metamorphosed into American hubris. Some of our sympathy has gone, and with it our ability to understand.

I was in Washington, not New York, and thus spared the real cataclysm. By comparison, we were lucky, suffering "only" 184 dead when American Airlines flight 77 crashed into the Pentagon – though that would have been the worst terrorist disaster in American history, had not two other planes struck the World Trade Centre less than an hour before.

But come this morning, beneath another brilliant blue sky, and those jumbled memories of panic and confusion will return – when a great cloud of smoke from the Pentagon billowed over the Potomac, when there were rumours of explosions by the Capitol, at the State Department, when the world's neo-imperial capital was reduced to chaos, its basic communications networks not functioning, its streets jammed with cars and terrified people seeking only escape, to make sure their children were safe.

As they fled, the President of the mightiest country in the world was himself jumping ignominiously from one Air Force base to another, at the orders of a secret service that, like the rest of us, had not the faintest idea whether, or how many, other rogue planes were loose in the American skies. For a short while that morning apocalypse seemed at hand. Then by early afternoon, a city shut down – its bars, shops, offices and restaurants closed, with just a few empty taxis roaming the empty streets.

Twelve months on, life's outward rhythms have resumed. They have to. People buy houses here, send their children to school. The charred gash torn by flight AA77 in the Pentagon's south-west facade has been repaired. Americans are still the friendliest people on earth, the readiest to return a smile. In that sense innocence has not been lost.

But whether you live in Washington or New York, you notice the change. After the destruction of its two most visible symbols, North America's greatest metropolis wonders: what next? In the capital, a double oppression hangs in the air. Part is the certainty that Washington is surely the preferred target for the next terrorist attack. And you are also aware that even as one "war" against an abstract noun grinds on with no victory in sight, another war approaches. This one admittedly is against a country with a name, identifiable on a map of the Middle East – but of equally unpredictable consequence, and whose rationale no one has properly explained.

This new war, moreover, if it comes, will have been hastened by the patriotism that 11 September also unleashed. Each of the multitude of Stars and Stripes that will surely flutter again today on houses in my Washington neighbourhood will make it a little easier for President Bush to topple Saddam Hussein by force.

Patriotism, in its noblest sense of community and coming together, showed America at its best after September 11, in the inspiring initial response to the attacks. But everywhere patriotism has a less pleasant side, enforcing conformity, sacrificing civil liberties in the name of an elusive security. So it has been in the US.

Patriotism, moreover, has also helped blind Americans to the Why behind the What – why their country, so admired in so many ways, should also be so detested. "They hate our freedom," Mr Bush repeats vacuously of the terrorists, as if unable to accept that America was anything less than uniquely virtuous and close to God. Thus does suffering increase self-righteousness.

But if his countrymen have some excuse for their ignorance of the fine points of US policy in the Middle East, their leader has none. Today, you may be sure, Mr Bush will expend few words on the policies that helped bring about September 11. Thus America will pursue its self-ordained course, convinced by innate optimism that everything will turn out right in the end.

Even this sombre first anniversary will not change this. First, to be sure, there will be grief and mourning, as thoughts dwell on those who died in a event beyond comprehension. But as the day progresses the pervasive fear will give place to more cheerful events – naturalisation ceremonies, concerts, even fireworks. Barring an anniversary outrage, grief and fear will give way to pride, at how this day of apparent weakness led to the display of unchallengeable US strength.

September 11, now designated "Patriot Day" by Mr Bush, may never become a fully-fledged federal holiday. But as the years go by, it will subtly assume a place alongside Thanksgiving Day and Independence Day as something more important than a mere day off. It will become a celebration of being American.