When otherwise sane and intelligent people affirm nonsense, it behooves us to inquire into the reason. Falling into that category is the recent finding by the American Jewish Committee that American Jews believe anti-Semitism is a greater threat than intermarriage by a margin of 57 percent to 38 percent.

In order to reach that conclusion, American Jews have to ignore the evidence in front of their eyes to a startling degree.

And they do. In a 1985 survey of Jews in Northern California, for instance, a full third expressed the belief that non-Jews would not vote for a Jewish candidate for Congress. At that time, three Congressmen from the area were Jewish. As Leonard Dinerstein concluded in his 1994 work "Anti-Semitism in America": "Today anti-Semitism in the United States is neither virulent nor growing. It is not a powerful social or political force. [It] has declined in potency and will continue to do so for the foreseeable future."

But if Poland has proven that anti-Semitism can persist even in the absence of Jews, says National Review literary editor David Klinghoffer, so America today proves that anti-Semitism persists in the minds of Jews even in the absence of anti-Semites.

At the same time, intermarriage — about which only a little more than a third of American Jews are concerned — coupled with low fertility rates, is projected to reduce American Jewry to between one-third and one-sixth of its present size within two generations.

The professed fear of resurgent anti-Semitism goes hand in hand with the elevation of the Holocaust to the defining element in Jewish self-identity.

All surveys of American Jewry place the Holocaust way ahead of any other factor in Jewish self-identity. Between 75 percent and 85 percent of American Jews rate the Holocaust as a very important factor in their sense of themselves as Jews, far higher than belief in God, Torah or Israel.

When they think of themselves as Jews, then, American Jews overwhelmingly identify themselves as victims. Their sense of themselves as Jews is purely negative, unless one thinks that a history of persecution tells us something fundamental about the victim. For them, Jews are nothing more than a social construct of anti-Semites, an occasion for the fevered conspiracy theories of Jew-haters.

And indeed Judaism is devoid of positive content for most American Jews.

Nearly 60 percent of Americans, according to a 1989 Gallup study of religiosity in America, view religion as very important in their lives; only 14 percent say that it is not at all important. Among Jews, however, the figures are nearly reversed: 30 percent say that religion is important; 35 percent that it is of no importance.

While American Jews claim to be concerned about anti-Semitism, they do not act upon those fears, apart from the occasional check in response to a scare letter from the Anti-Defamation League or some other Jewish defense group.

But if American Jews are, in their heart of hearts, not really that scared of resurgent anti-Semitism, why do they insist on keeping the spectre of anti-Semitism alive? Why do they react so strongly to every crackpot Holocaust denier who would deny them their status as history's champion victims?

The answer is that anti-Semitism is a convenient balm for the pangs of conscience. Anti-Semites, even imagined ones, provide confirmation that one is a proud, loyal Jew, linked to all those other Jews throughout history, who knew too well what real Jew-hatred was. To paraphrase Descartes: I am hated, therefore I am. If Hitler would have killed my grandchild, let no one deny that my grandchild is Jewish.

It is more convenient to focus on what others do to us, or want to do, than to consider what we are doing to ourselves. Far easier to conjure up imaginary Hitlers than to wonder whether we have failed when our children intermarry and show little interest in even the vague ethnic identity with which we provided them.

As long as we can cite the names of relatives killed by the Nazis, we assure ourselves that our Jewish bona fides are intact, and we are indeed proper heirs to 2,000 years of victimhood.

We focus on the Holocaust as the defining event in Jewish history without even asking ourselves the real question: What power did our ancestors find in their Judaism that enabled them to withstand and survive all the Torquemadas, Chmelnickis and Hitlers?

To ask that question would force us to admit that Judaism has content and is not defined by our enemies. That admission would, in turn, force us to confront the possibility that we have failed our ancestors by not even inquiring into the source of their spiritual strength.

Jewish "worry" about anti-Semitism would be funny but for the deeper tragedy it seeks to mask — Jews unable to define themselves except in terms of the hatred of others. By lulling American Jews into thinking of themselves as good Jews, even as they make peace with skyrocketing intermarriage and their own disappearance, the illusion of widespread anti-Semitism ensures the continuation of those trends.