Is it conceivable that Al Qaeda, as defined by President Bush as the center of a vast and well-organized international terrorist conspiracy, does not exist?

To even raise the question amid all the officially inspired hysteria is heretical, especially in the context of the U.S. media's supine acceptance of administration claims relating to national security. Yet a brilliant new BBC film produced by one of Britain's leading documentary filmmakers systematically challenges this and many other accepted articles of faith in the so-called war on terror.

"The Power of Nightmares: The Rise of the Politics of Fear," a three-hour historical film by Adam Curtis recently aired by the British Broadcasting Corp., argues coherently that much of what we have been told about the threat of international terrorism "is a fantasy that has been exaggerated and distorted by politicians. It is a dark illusion that has spread unquestioned through governments around the world, the security services and the international media."

Stern stuff, indeed. But consider just a few of the many questions the program poses along the way:

•  If Osama bin Laden does, in fact, head a vast international terrorist organization with trained operatives in more than 40 countries, as claimed by Bush, why, despite torture of prisoners, has this administration failed to produce hard evidence of it?

•  How can it be that in Britain since 9/11, 664 people have been detained on suspicion of terrorism but only 17 have been found guilty, most of them with no connection to Islamist groups and none who were proven members of Al Qaeda?

•  Why have we heard so much frightening talk about "dirty bombs" when experts say it is panic rather than radioactivity that would kill people?

•  Why did Defense Secretary Donald Rumsfeld claim on "Meet the Press" in 2001 that Al Qaeda controlled massive high-tech cave complexes in Afghanistan, when British and U.S. military forces later found no such thing?

Of course, the documentary does not doubt that an embittered, well-connected and wealthy Saudi man named Osama bin Laden helped finance various affinity groups of Islamist fanatics that have engaged in terror, including the 9/11 attacks. Nor does it challenge the notion that a terrifying version of fundamentalist Islam has led to gruesome spates of violence throughout the world. But the film, both more sober and more deeply provocative than Michael Moore's "Fahrenheit 9/11," directly challenges the conventional wisdom by making a powerful case that the Bush administration, led by a tight-knit cabal of Machiavellian neoconservatives, has seized upon the false image of a unified international terrorist threat to replace the expired Soviet empire in order to push a political agenda.

Terrorism is deeply threatening, but it appears to be a much more fragmented and complex phenomenon than the octopus-network image of Al Qaeda, with Bin Laden as its head, would suggest.

While the BBC documentary acknowledges that the threat of terrorism is both real and growing, it disagrees that the threat is centralized:

"There are dangerous and fanatical individuals and groups around the world who have been inspired by extreme Islamist ideas and who will use the techniques of mass terror — the attacks on America and Madrid make this only too clear. But the nightmare vision of a uniquely powerful hidden organization waiting to strike our societies is an illusion. Wherever one looks for this Al Qaeda organization, from the mountains of Afghanistan to the 'sleeper cells' in America, the British and Americans are chasing a phantom enemy."

The fact is, despite the efforts of several government commissions and a vast army of investigators, we still do not have a credible narrative of a "war on terror" that is being fought in the shadows.

Consider, for example, that neither the 9/11 commission nor any court of law has been able to directly take evidence from the key post-9/11 terror detainees held by the United States. Everything we know comes from two sides that both have a great stake in exaggerating the threat posed by Al Qaeda: the terrorists themselves and the military and intelligence agencies that have a vested interest in maintaining the facade of an overwhelmingly dangerous enemy.

Such a state of national ignorance about an endless war is, as "The Power of Nightmares" makes clear, simply unacceptable in a functioning democracy.