Dueling demographers have drawn their weapons -- conflicting surveys -- in the latest round of an ongoing quarrel over the future of American Jewry.

Gary Tobin, president of the Institute for Jewish and Community Research, brandished the first batch of recent data several weeks ago, from which he divined that the country's Jewish population has been underestimated for years, that there are fully 6.7 million Jews among the 288 million residents of the United States. Alluding to the rather broad calipers he used to measure Jewishness -- he included as Jews not only people with a Jewish father but a non-Jewish mother but anyone who said he or she was culturally Jewish and -- Dr. Tobin says that "Jews are not disappearing, they're transforming."

The core population of American Jews is aging and producing fewer children than it needs to replace itself.

Dr. Tobin's study was based on a survey of 250 households. Following close on its heels came the release of preliminary results of the much-awaited and long-delayed National Jewish Population Survey (NJPS), based on several thousand. It presents a different picture, of a substantially smaller American Jewish population -- 5.2 million.

Whichever number is closer to the truth, however, the NJPS study revealed something else more important: the core population of American Jews seems to be shrinking -- aging and producing fewer children than it needs to replace itself. The NJPS figures indicate a decline of 300,000 Jews since the last major nationwide study a decade ago, and an average birthrate of 1.8 children per couple; 2.1 is considered the minimum "replacement level" average.

Some, including Dr. Tobin, feel that what the Jewish community needs is to redefine itself, to consider broadening the sociological definition of "Jewish" beyond not only those traditionally considered Jewish (by their birth to a Jewish mother or proper conversion), but beyond even the NJPS's already stretched-thin sociological definition.

Concurring with his advice to widen the Jewish tent is Dr. Egon Meyer, the director of the Center for Jewish Studies at the graduate center of the City University of New York. Dr. Meyer also heads the Jewish Outreach Institute, whose motto is "Welcoming Interfaith Families into the Jewish Community."

The premise of such "inclusivists," though, seems to be that the core Jewish community's ultimate goal, in and of itself, should be to achieve larger Jewish numbers.

However, from a traditional Jewish perspective, that is precisely wrong. What matters is not our numbers at all but rather our peoplehood.

The "more Jews the merrier" approach essentially regards the Jewish people as an interest group. The "we are a people" approach sees us more like a family, basing itself on an essential and strong genetic component, yet allowing selected others -- conditional on their solid and solemn commitment -- to join as well.

Orthodox Jews consider even the most alienated Jew to be their brother or sister, fully worthy of their assistance, love and outreach.

Ironically, the traditional approach concurs in some ways with the methodology of the "inclusivists." Just as they consider a Jew who has strayed entirely from Judaism to remain a Jew, so do Orthodox Jews consider even the most alienated Jew to be their brother or sister, fully worthy of their assistance, love and outreach. On the other hand, though, there are clear boundaries, those of the Jewish religious tradition, that define membership in Klal Yisrael, the communal Jewish family. Being married to a Jew is not sufficient; nor is being born to a Jewish father; nor is undergoing a course or ceremony that does not satisfy the Torah-sourced and time-honored standards for conversion.

The portion of the NJPS that will address the growth and level of Jewish commitment of specific groups within the Jewish people is not scheduled for release until the end of November. But if it reflects reality, it will likely show that the more traditional Jewish community is waning neither in numbers, birth rate nor commitment to Jewish practice. That fact should reiterate to the larger Jewish community concerned about continuity the importance of Jewish education and religious practice.

But it would be healthy, too, were it to bring us all to more seriously consider the wisdom of the traditional approach to understanding Jewish peoplehood: that we are not a interest group but rather a family, that the definition of Klal Yisrael in our past might well be the most meaningful one for gauging our present -- and for planning our future.