In the three years since 11 September, everything and nothing has changed

If the weather forecasters are correct, today will dawn clear cool and beautiful along the US east coast - just as did that terrible 11 September of 2001, when hijacked commercial airliners smashed into the World Trade Centre and the Pentagon, and in the process changed the world.

If the weather forecasters are correct, today will dawn clear cool and beautiful along the US east coast - just as did that terrible 11 September of 2001, when hijacked commercial airliners smashed into the World Trade Centre and the Pentagon, and in the process changed the world.

Today it seems not a mere three years, but an age ago. Everyone remembers where they were as they watched in horror the collapse of the two great silver towers, symbols of the city that itself symbolised US economic might and global capitalism. Now, more than ever, the event appears a watershed between eras. Finally, we understood that the enemy of our comfortable Western societies was not a long discredited communism, but a desperate militant Islam, the perverted by-product of the failings within the Arab world, and its humiliations from without.

So began America's "war against terror". Events tumbled one after the other. First, war in Afghanistan to topple the Taliban regime which had harboured al-Qa'ida; next, President Bush's designation of his "axis of evil" consisting of Iraq, Iran and North Korea; then the invasion of Iraq - based, we now know, on a farrago of incorrect intelligence and downright lies. All the while, terrorist strikes continued. Not in the US, which despite constant alarms has suffered no attack since 9/11, but around the world: Bali and Istanbul, Riyadh, Madrid and Casablanca, and just this week Jakarta. The conflict between Israel and Palestine has become even more violent - as has the festering crisis around Chechnya, culminating in last week's atrocity at the school in Beslan.

The Israeli government presents its struggle with the Palestinians as at one with America's war against al-Qa'ida. President Putin describes Beslan as "Russia's 9/11" and, like President Bush, arrogates the right to carry out preventive strikes against suspected terrorists and their bases beyond Russia's borders. In their different ways, both developments are direct consequences of what happened in Washington and New York that perfect September morning of 2001.

In another sense, however, we are back where we started. The initial reaction to 11 September was an outpouring of sympathy around the world for the stricken United States, epitomised by Le Monde's famous headline "We are All Americans Now". The immediate assumption was that the devastating attacks signalled a shift in the balance of global power, of a new age of "asymmetrical warfare", in which the mighty superpower had become a helpless victim.

The attacks did usher in a new era - not, however, of American weakness, but of American assertiveness and apparently limitless power. Quickly, the US gave the lie to Afghanistan's reputation as a humbler of foreign empires. Next up was Saddam Hussein, whom Washington had determined to remove for reasons still not satisfactorily explained.

In less than 18 months, President Bush achieved the remarkable feat of squandering all the post-11 September goodwill for the US, and making his country more detested abroad than at any time in its modern history. But it didn't seem to matter, as the President rode roughshod over the United Nations and world opinion, ordering an invasion that conquered Baghdad in exactly three weeks. Three weeks after that, Mr Bush appeared aboard the aircraft carrier USS Abraham Lincoln to proclaim Mission Accomplished in this chapter of the "war on terror". The celebration was premature.

As we know all too well, post-war Iraq has been a disaster. The civil war and national disintegration of which the invasion's opponents warned are now real possibilities. Thus far, the disaster has had little effect on Mr Bush's electoral fortunes. Once more, he can thank 11 September, which has allowed him to present Iraq, warts and all, as another battle in the "war on terror", in which America is marching steadily towards certain ultimate victory.

But is it? On the eve of today's third anniversary, who should emerge from hiding than Ayman al-Zawahri, second in command of al-Qa'ida, arguing in a professional, recently produced video how America is "caught between two fires" in Iraq - faced with a choice between humiliating withdrawal, and a continuing occupation that will make the US even more unpopular among the very Iraqis its troops are supposed to be protecting.

From the rostrum of the Republican convention and at his every campaign stop, Mr Bush proclaims that his actions since 11 September 2001 have made America and the world safer. But the opposite is surely true. Islamic terrorists have not launched a subsequent attack on US soil (although US intelligence specialists are convinced one will occur, perhaps during the climax of the election campaign, within the next two months). But the taunts of al-Zawahri remind the world that Osama bin-Laden, America's public enemy No. 1, no longer mentioned by the President, is still at large.

There is hardly a counterterrorist specialist who does not believe that the invasion of Iraq has increased the terrorist risk. Yes, existing terrorists are captured. But the occupation has fuelled resentment of America throughout the region. New terrorists are recruited; new groups coalesce across the Islamic world. In that sense, we are back to 10 September 2001.

The world may have changed, but three years on from 11 September we face more of the same. For all his swaggering campaign rhetoric, the President must realise that the US needs to rebuild the diplomatic and emotional bridges it has burned, in Europe and beyond. Alas, sympathy so rashly squandered will not be easily regained.