The enormity of the attacks on America was shockingly and immediately clear to millions of people watching around the world, transfixed by the image of New York's twin towers buckling and crumbling into dust.

It has become a cliche, repeated in countless headlines, to describe September 11 as the Day that Changed the World.

But for some historians the jury is still out as to whether the events of a year ago, devastating and traumatic as they were, represented a one-off episode in history or a decisive turning point.

"Everybody is saying that this changed America for ever, and that just seems to me a kind of nonsensical statement. It's not clear in what sense anyone means that, other than that they're going to remember this for a long time," said Professor Francis Fukuyama of Johns Hopkins University in the United States.

"I can't see how this fits into any historical context. It's an isolated act, perpetrated by what is in effect a secret society," said British historian Professor Lord Robert Blake.

ECHOES OF PAST WORLD CRISES

Certainly the public statements of the leading September 11 protagonists have been charged with a sense of historic mission, with President George W. Bush casting America as the champion of the free world and defender of civilisation.

US Defense Secretary Donald Rumsfeld recently compared Bush's pursuit of Iraqi President Saddam Hussein, whom Washington accuses of developing weapons of mass destruction, with Winston Churchill's dogged stand against Hitler.

Historians typically are wary of such analogies, but some do see parallels between current events and past world crises.

British professor Eric Hobsbawm compared the catalysing effect of the September 11 attacks with that of the 1914 assassination of Austrian Archduke Franz Ferdinand in Sarajevo, the spark that ignited World War One.

In the same way that the great powers chose Sarajevo as the occasion for a European war that had long been expected, Hobsbawm said, the United States made September 2001 the moment to assert itself as a military power capable of bringing massive force to bear anywhere in the world.

This was not a sudden impulse, he said, but the expression of a doctrine that began to take shape under the first Bush administration to combat insurgency, terrorism and drug trafficking.

"I think in this respect the 11th of September was the occasion for the Americans to say: well, we've been preparing it, this proves that we need it^ "What made it a turning point was that the USA chose to make it one."

CONTRAST WITH PEARL HARBOR

The other often drawn analogy has been with the Japanese attack on Pearl Harbor that prompted America to enter World War Two. But here again, some historians see crucial differences as well as parallels.

"It's very different from Pearl Harbor. Pearl Harbor instilled an idea that the United States was caught up in a worldwide crisis... It declared war on Japan and Germany immediately as part of the same threat," said Professor Lord Kenneth Morgan, a specialist in 19th and 20th century British and American history.

In contrast with the collaborative Allied effort against Hitler, the current crisis would promote a "Fortress America" mindset. Faced with "a more impenetrable and unknowable adversary who might crop up anywhere", the United States would look to its own resources and pursue a more self-sufficient and quasi-isolationist stance, he said.

In telephone interviews with Reuters, Fukuyama, Hobsbawm, Morgan and Blake all agreed there was no sign that the September 11 attacks had weakened the United States or undermined its global pre-eminence.

On the contrary, they saw a stronger America emerging,purposeful and assertive in its foreign policy.

To Hobsbawm, a Marxist historian who says he has "an old-fashioned prejudice against empires", America's current international domination is without precedent, outstripping even British imperial supremacy.

"I think that is the main danger. They have to learn, as the British did in the 19th century, that there are limits even to the most unchallengeable military power."

UNWINNABLE WAR ON TERROR

For Morgan and Blake, the US "war on terror" is one that can never be won, if history is any guide.

"I don't think it can be completely won, because there's a sense in which it never has been. You had, during the 19th century, the threat of anarchists who were engaged in trying to blow up the heads of monarchies and in some cases were successful, like (Russian Tsar) Alexander II," Blake said.

"I don't think you can eliminate acts of terror entirely. You can certainly take great precautions against them, and that is the most you can do."

For Fukuyama, the judgment of historians on September 11 will hinge on what happens next: specifically, on whether the United States now goes to war with Iraq and whether that leads to quick victory or a Vietnam-style quagmire.

The other struggle he sees ahead is between radical Islamism, as represented by Osama bin Laden and al Qaeda who were blamed by Washington for the September 11 attacks, and liberal currents within the Islamic world.

(China Daily September 9, 2002)