The other day, when I made a reference to "the war on terrorism," a Democratic friend of mine objected: "It's not a war." I never found out what he thought it was -- the conversation wandered off in other directions -- but the question keeps nagging away in the back of my mind. If it isn't a "war," what is it?

I have no particular hang-up about calling it a war. Call it a "fracas," if you prefer, or a "brouhaha." But it is certainly something, and deserves a name. And I will concede that, if it is a war, it is a most unusual example of the species.

In an ordinary war, one nation-state takes up arms against another. The cause will presumably be important, but it needn't be earth-shaking -- a boundary dispute will do. The battles will be waged between organized military units, using a wide variety of technologies, and sooner or later one side will win.

The current fracas passes not a single one of these tests. The aggressor is militant Islam, which is not a nation-state, but a religious conviction on the part of millions of individuals scattered, in greater or smaller numbers, among a wide variety of nations. And the "war" it is waging is not so much against a nation-state or states as against a cultural frame of mind: the culture of "the West," which the militants believe it is their obligation to destroy. Not merely "defeat," you understand, but destroy.

The issue, in other words, could hardly be more fundamental. In the view of the Islamic militants, the West is a suppurating vat of evil, armed with technologies that have enabled it to overwhelm the rest of the world and humiliate Islam. They consider it their obligation to eradicate it and replace it, the world over, with the one true religion.

This is obviously a tall order, but Osama bin Laden and other creative thinkers in the militant ranks have studied the problem carefully and think they see a way of bringing it about. They cannot possibly overwhelm the West militarily in the conventional way. But they believe that the West -- and above all, its leading nation, the United States -- is effete, decadent and corrupted by its creature comforts. They note that for more than 30 years the United States has fled every battlefield on which it was being forced to sustain serious casualties. There is good reason to believe that Iraq may be next.

By way of contrast, the Islamic militants are not in the least afraid of death. On the contrary, they have a virtually endless supply of willing suicides, ready to crash passenger planes into buildings, or simply strap explosives to their bodies and detonate them in the midst of their enemies. In Israel, Iraq and Afghanistan, and other countries all over the globe, they have developed these techniques into what amounts to a whole new technology of war.

In this sort of "war," there is no nation-state against which the West can stage a counterattack (though there are, to be sure, rogue nation-states like Iran, ready to aid the militants). There is no capital city that can be conquered and occupied. There is not even a political leadership sufficiently unified and effective to bring about surrender, assuming it could be forced to try. The enemy is everywhere, and therefore, in effect, nowhere.

Who can say with confidence that bin Laden is wrong in his calculations? At the moment, he almost certainly thinks he is winning. If the Democrats succeed in forcing a "redeployment" of American forces in Iraq to some less inhospitable area (probably home), the Middle East will rapidly fall under the sway of the militants, the Muslim influence in Europe and much of the rest of the world will grow and become more malignant, and the United States will be left to confront its fate alone.

So the "war on terrorism" may not be a war in the conventional sense. But a day may come, ironically, when we will wish it were.