I have just entered the United States. Since I was on a so- called J-1 visa, this was quite an achievement. First I had to fill in a form asking my host university to send me another form.

Armed with that form, I filled in three further forms, including such obviously relevant information as my brother's telephone number, and the names of two people who could verify this information.

Then I had to go to Barclays bank to get a special receipt for paying the fee. Then I had to supply a passport photograph two inches square in which "the head (measured from the top of the hair to the bottom of the chin) should measure between 1 inch to 1 inches (25mm to 35mm) with the eye level between 1 1 18 inch to 1 inches (28mm and 35mm) from the bottom of the photo". Only a few photoshops do these and, once found, Snappy Snaps charged me 24.99 pound sterling for a double set. Snappy, indeed. The first time you apply, you also have to go for an interview at the embassy.

Finally armed with this precious patent of nobility, I arrived at San Francisco airport, where I was fingerprinted and photographed. Last year, I was taken aside for further investigation, while at the next desk an official of the department of homeland security reduced a girl to a nervous wreck by intrusive questioning about what she would be up to with her American boyfriend. And she, like me, was from Britain, the United States' closest ally. Imagine what it's like if you come from Libya or Iran.

Yes, I know that the United States was attacked by terrorists on September 11, 2001, and some of those terrorists had entered the US on J-1 visas. I understand, obviously, that the country has had to tighten up its security controls. But this is more than just a personal grouse. Heads of leading American universities have publicly complained that such bureaucratic and intrusive procedures are reducing the number of foreign students willing and able to come to study in the US.

(I have heard it argued in London that this creates a significant opportunity for British universities.) This raises the larger question of whether the United States' "soft power", its power to attract others and to get them to do what it wants because they find it attractive, has been diminished by the way the Bush administration has reacted to the 9/11 attacks. That, in turn, raises the even larger question of who is winning this "war": Al Qaeda or the US?

"God bless America," wrote the poet Philip Larkin, "so large, so friendly and so rich." And American hyperpower, by contrast with the one-dimensional superpower of the Soviet Union, has always depended on having all three dimensions: military, economic and "soft". The soft power of a country is more difficult to measure than its military or economic power, but one yardstick is what I call the "Statue of Liberty test".

In this test, countries are rated by the number of people outside who want to get into them, divided by the number of people inside who want to get out. Thus, during the cold war, many people wanted to emigrate from the Soviet Union, while very few wanted to go and live there, whereas hundreds of millions wanted to enter America and very few to leave it. By this rough measure, America still has bags of soft power.

Yet its overall attractiveness surely has been diminished, not just by such bureaucratic procedures, but by Guantanamo, by Iraq, by a certain harsh, militarist, nationalist approach to world affairs, and by a mistaken belief that the "war on terror" can be won mainly, if not solely, by military, intelligence and police means.

If you look at the results of the world-wide survey conducted by the Pew Research Centre, you can see that resentment of America around the world has reached unprecedented levels in the last two years. The Bush administration has imperilled the economic dimension of American power, by running up $500bn trade and budget deficits while increasing military spending to $400bn, and it has largely neglected the third, soft dimension.

Meanwhile, even the one in five Americans who possess a passport have become more reluctant to travel outside North America. To give just one small example: American customers of Avis car rentals in Europe are down 40 per cent on 2000 levels. There's a real sense of a "Fortress America".

Could the liberal, multilateralist, French-speaking John Kerry, who launches his campaign in earnest at the Democrats' convention in Boston next week, change all this, and restore a Kennedyesque glow to America's image in the world? I find many people in Europe already answer that question with a firm no. Something deeper has changed, they say. Even if America reverts to its previous form, attitudes towards America will not.

But I wouldn't be so sure. Perhaps it's just the effect of sitting here in the Californian sunshine, watching this extraordinary multi-ethnic society working all around me, but I think America's underlying attractions are still all there - damaged by 9/11, diminished by economic competition from booming Asia, but still formidable.

If Kerry can summon a spark of charisma, aided by his appealing running mate John Edwards, and if the monstrous ego of Ralph Nader will kindly fall under an appropriately eco-friendly bus, the Democrat has a chance of reminding us that the other America still exists. And much of the world, even the Arab and Muslim world, will respond.

Which is why, if Osama bin Laden is still in a fit state to make political calculations, he must be backing an election victory for George Bush. The object of the terrorist is often to reveal the "true" repressive character of the state against which the terror is directed, and thus win further support for the terrorists' cause.

If the United States had just acted in Afghanistan, and then concentrated on hoovering-up the remains of Al Qaeda, the United States might clearly be winning the "war on terror" today. But, as Osama must have hoped, the Bush administration overreacted, and thus provided, in Iraq and Guantanamo, recruiting sergeants for Al Qaeda of which Osama could only dream.

So in this looking-glass world of backhanded ironies, Republicans are covertly supporting their most extreme opponent, Ralph Nader, because he will take votes from John Kerry, and Al Qaeda terrorists will be backing Bush, because he's their best recruiter. But can they do anything to affect the outcome of an American presidential election? Of course they can. A major terrorist attack on the American homeland a few days before November 2 would almost certainly not have the effect that the Madrid pre-election bombing had, sending swing voters to the anti-war opposition.

In a recent opinion poll for the Economist, handling the "war on terror" was one of the few areas in which American voters favoured Bush over Kerry. It seems likely there would be a wave of patriotic solidarity with the incumbent. In short, Bush's election chances may depend on the ruthless ingenuity of Al Qaeda, while Kerry's election chances may depend on the ability of Bush's department of homeland security to combat it.-Dawn/The Guardian News Service.