Since last 11 September, the Bush administration has told the American people, America has been at war. But this war has a rather peculiar nature. It seems to be, given the nature of the enemy, a war with no foreseeable end. What kind of war is that?

There are precedents. Wars declared in recent years on such enemies as cancer, poverty, and drugs are understood to be endless wars. As everyone knows, there will always be cancer, poverty, and drugs. And there will always be despicable terrorists, terrorists who are mass murderers, such as those who perpetrated the attack last 11 September, as well as freedom fighters once called terrorists (as was the French resistance by the Vichy government, and the ANC and Nelson Mandela by the apartheid South African government) but subsequently relabelled by history.

When a president of the United States declares war on cancer or poverty or drugs, we know that "war" is a metaphor. Does anyone think that this war - the war that America has declared on terrorism - is a metaphor? But it is, and one with powerful consequences. The war has been disclosed, not actually declared, since the threat is deemed to be self-evident.

Real wars are not metaphors. And real wars have a beginning and an end. Even the horrendous, intractable conflict between Israel and Palestine will end one day. But the war that has been decreed by the Bush administration will never end. That is one sign that it is not a war, but, rather, a mandate for expanding the use of American power.

When the government declares war on cancer or poverty or drugs, it means the government is asking that new forces be mobilised to address the problem. It also means that the government is not going to do a whole lot to solve it. When the government declares war on terrorism - terrorism being a multinational, largely clandestine network of enemies - it means that the government can do what it wants. When it wants to intervene somewhere, it will. It will brook no limits on its power.

The American suspicion of "foreign entanglements" is very old. But this administration has taken the radical position that all international treaties are potentially inimical to the interests of the United States - since by signing a treaty on anything (say, environmental issues, or the conduct of war and the treatment of prisoners, or a world court), the United States is binding itself to obey conventions that might one day be invoked to limit America's freedom of action to do whatever the government thinks is in the country's interests. Indeed, that's what a treaty is: it limits the right of its signatories to complete freedom of action on the subject of the treaty. It has not, up to now, been the avowed position of any respectable nation-state that this is a reason for eschewing treaties.

Describing America's new foreign policy as actions undertaken in wartime is a powerful disincentive to having a mainstream debate about what is actually happening. This reluctance to ask questions was already apparent in the immediate aftermath of the attacks last year. Those who objected to the jihad language used by the American government (good versus evil, civilisation versus barbarism) were accused of condoning the attacks, or at least the legitimacy of the grievances behind the attacks.

Under the slogan "United We Stand", the call to reflection was equated with dissent, dissent with lack of patriotism. Such indignation suited those who took charge of the Bush administration's foreign policy. The aversion to debate among the principal figures in the two parties continued to be apparent in the run-up to the commemorative ceremonies on the anniversary of the attacks - ceremonies viewed as the continuing affirmation of American solidarity against the enemy.

The comparison between 11 September 2001 and 7 December 1941 has never been far from mind. Then too, America was the object of a lethal surprise attack that cost many - in this case, civilian - lives, more than the number of soldiers and sailors who died at Pearl Harbor. However, I doubt that great commemorative ceremonies were felt to be needed to keep up morale and unite the country on 7 December 1942. That was a real war, and one year later it was still going on.

This is a phantom war, a war at the pleasure of the Bush administration, and therefore needed an anniversary. Such an anniversary would serve a number of purposes. It would be a day of mourning. An affirmation of national solidarity. But of one thing we could be sure. It would not be a day of national reflection. Reflection, it was said, might impair our "moral clarity". It was necessary to be simple, clear, united. Hence, there were to be no words; rather, there were to be borrowed words, such as the Gettysburg Address (claimed by both political parties), from that bygone era when great rhetoric was possible.

But Abraham Lincoln's speeches were not just inspirational prose. They were bold statements of new national goals in a time of real, terrible war. The second inaugural address dared to herald the reconciliation between North and South that must follow Northern victory in the Civil War. The primacy of the commitment to end slavery was the point of the exaltation of freedom in the Gettysburg Address. But to cite the great Lincoln speeches at the commemorative ceremonies of 11 September, completely emptied them - in true postmodernist fashion - of meaning. They were now gestures of nobility, of greatness of spirit. What they were being great about was irrelevant.

It is all in the grand tradition of American anti-intellectualism: the suspicion of thought, of words. And it very much serves the purposes of the present administration. Hiding behind the humbug that the attack of last 11 September was too horrible, too devastating, too painful, too tragic for words - that words could not possibly do justice to our grief and indignation - our leaders have a perfect excuse to drape themselves in borrowed words voided of content. To say something might be controversial. It might actually drift into some kind of statement and therefore invite rebuttal. Not saying anything is best.

And there have been pictures. Lots of pictures. As old words are recycled, so are the pictures of a year ago. A picture, as everyone knows, is worth a thousand words. We relive the event. There are interviews with survivors, and with the members of the families of those who died in the attacks. It's "closure" time in the gardens of the west. (I used to think the piece of verbal flummery that represented the great current threat to seriousness and to justice was "elitist". I've come to regard "closure" as just as phoney and odious.) Some have achieved closure, others have refused it, needing to continue with the mourning. Then there was the reading aloud by city officials of the names of those who died in the twin towers - an oral version of the most admired monument of mourning in the United States, Maya Lin's interactive black stone screen in Washington DC, on which is incised (for reading, for touching) the name of every American who died in Vietnam. There have been other bits of linguistic magic, such as the decision just announced that the international airport across the river in New Jersey, from where United Flight 93 took off on its doomed flight, will henceforth be called Newark Liberty Airport.

Let me be even clearer. I do not question that there is a vicious, abhorrent enemy which opposes most of what I cherish - including democracy, pluralism, secularism, the absolute equality of the sexes, beardless men, dancing (all kinds), skimpy clothing, and, well, fun. Not for a moment do I question the obligation of the American government, as of any government, to protect the lives of its citizens. What I do question is the pseudo-declaration of pseudo-war. These necessary actions should not be called a "war". There are no endless wars. But there are declarations of the extension of power by a state that believes it cannot be challenged.

America has every right to hunt down the perpetrators of these crimes and their accomplices. But this determination is not necessarily a war. Limited, focused military engagements abroad do not translate into "wartime" at home. There are better ways to check America's enemies, less destructive of constitutional rights and of international agreements that serve the public interest of all, than continuing to invoke the dangerous, lobotomising notion of endless war.

Susan Sontag's latest book, Where the Stress Falls, is published by Jonathan Cape (£17.99)

(c) Susan Sontag 2002