A recent national poll indicated that 35 percent of Democrats believe that President Bush knew in advance about Al Qaeda's attack on New York and Washington on Sept. 11, 2001. What are we to think about this staggering statistic?

There are those who simply dismiss the poll as inaccurate, and certainly it is true that plenty of public opinion polls are sloppily conducted, misleading or just plain wrong. We can hope that is true this time, but it would be a mistake to count on it. There are many factors at work here, and some of them suggest that the poll is quite probably correct.

In the first place, the recent notorious polarization of American politics, generated by Republican successes and inflamed by the media, has created a situation in which the hatred of George W. Bush, if not unprecedented, is surely rare. We are assured by many people that this man, having twice achieved the pinnacle of American politics, has no higher ambition than to stuff the pockets of his rich Texas friends with additional millions of dollars in the form of tax cuts and other subsidies. It would be interesting to know what percentage of Americans, if told that there was evidence that Bush regularly molests children, would be willing to entertain the idea.

I suspect, however, that there is another, far more important dynamic at work here. If there is one thing many Americans hate and fear worse than anything else, it is being deceived. This emotion is deeply rooted, and at a certain level positively useful. The legend of the successful horse-trader, who always gets the better of a bargain, is one of the oldest in our collective mythology. And at a higher level, there is no one any sensible person distrusts more, or with more reason, than the typical politician. If we don't trust what they say (and often we don't), that is because so many of them have, historically, lied themselves blue in the face.

So it's not surprising that, for many Americans, the default setting for listening to a politician's words is to disbelieve them. There's a good chance that we're right to do so, and if it turns out that this time he or she was telling the truth -- well, fine, but at least we won't feel like a fool for being suspicious.

Therefore, if some pollster comes along and asks a confirmed Democrat whether he thinks Bush knew about 9/11 in advance, there is a primitive instinct that warns him not to rule the possibility out. If, as is altogether likely, he despises Bush for a whole set of different (and, it may be, far better) reasons, the impulse to believe the charge about 9/11 will gain added force. If there is any doubt about the matter, why give him the benefit of it?

I doubt that many of the 35 percent of Democrats who told the pollsters they believe that Bush knew about 9/11 in advance would welcome being cross-examined on the subject, or defend their contention very strongly if they were. After all, it would take little short of a monster to know in advance about the attack and yet do nothing, in order to scare the American people into supporting an American attack on Iraq or some other political objective. With at least part of our brain, we know better than that. To go along with such a suggestion about Bush is surely better understood as a sort of reflexive spasm of contempt for the man, rather than a considered judgment of his likely behavior.

But it is chilling, nonetheless, to realize that a significant portion of the American public is willing to say what that poll reported them as saying. Fortunately, most of us are not. I have an abysmally low opinion of many politicians, but I can't think of a single one in either party whom I would suspect for a moment of being willing to ignore foreknowledge of 9/11 for mere political advantage.

I would rather have one fool me than believe that of him.