American Jewry is not about to disappear. Those who make that argument base themselves on an unimaginatively conventional definition of Judaism. They fail to understand that we live in the 21st century where centripetal forces work alongside centrifugal ones. The attempt to present the diminishing numbers of American Jews linearly stems from a willingness on the part of the non-Orthodox, as well as the secular American Jewish majority, to accept the criteria on the eternal question of who is a Jew set by the Orthodox minority. The Orthodox definition is just one entry gate into the Jewish people. There must also be an alternative definition that would enable non-religious non-Jews to become non-religious Jews. I am certain that the secular Jewish community will eventually stop complying with the criteria established by the various Jewish denominations. Secular Jews could then recognize as Jews people whose fathers are Jewish, or people whose children and spouses are Jewish - if they chose to be considered Jews. OTHERS WISHING to join the Jewish people, but not necessarily the Jewish religion, would be able to do so if they demonstrated a bond to Judaism. They might do so, say, by affiliating with a Jewish community federation. Whatever the approach, they'd obviously be expected to study Jewish history and have some familiarity with the Hebrew language. If the situation is liberalized, we can expect an increase in the number of Jews in America. As for those Israeli leaders who cherish Jewish continuity, their role would be to help open a secular door to the Jewish people in both Israel and the Diaspora. The decrease in the number of Jews is not the result of large numbers of Jews converting out because they have been favorably exposed to another religion. It is simply that Jews represent a minority wherever they live and they marry non-Jews; since they accept rabbinical definitions regarding the matter of their children's Jewishness, they are seen as lost to the Jewish people. And instead of drawing these people and their children closer to us, we drive them away, behaving like Tevye in Fiddler on the Roof, who sat shiva for his daughter Hava who married a goy - even though her children would have been Jewish according to Halacha. AND WHILE I'm on the subject of the urgent need for change, the recent gathering of the World Zionist Congress raises a number of important issues. Zionism is not dead and must not die, but some Zionist institutions have become atrophied or lacking raison d'etre. These days one can be a Zionist for an entire lifetime without giving a thought to immigrating to Israel. Meanwhile, the Jewish Agency, once an important scaffolding that aided in the establishment of the state, continues to ignore the fact that the state already exists, and it is still trying to serve in its original role. Instead of becoming a vital, animated platform where a serious debate can be held about how to assure the future of the Jewish people, about how to use modern means to provide a Jewish education, about the creation of a virtual global Jewish community in the Internet age, about the ways to strengthen weak communities and fight anti-Semitism wisely, the agency sanctifies and perpetuates obsolete frameworks that have become completely irrelevant. IT'S INTERESTING that the 35 World Zionist Congress sessions were virtually ignored by the Israeli media. The fact is that the Jewish Agency and Zionist federations are irrelevant organizations. Granted they are run by good people with good intentions who work hard in such areas as welfare and absorption, but this role is by right the responsibility of the Israeli government. A small executive ministry would be more than enough to carry out everything that the existing large, cumbersome bureaucracy does today. The Jewish Agency is fearful of anything new, so much so that it was the greatest opponent of the birthright israel program when I first proposed it more than 10 years ago. Only when it saw that the program was being launched without it did it decide to come on board. AND WHILE we are being creative, let's consider the world Jewish forum that President Moshe Katsav is trying to establish. It should replace many existing institutions and enable a meaningful debate on the state of the Jewish people. Alongside it, a new American-Israeli forum should be formed. There is no reason why the two largest Jewish communities - Israel's and America's - should not form a shared institution, an American-Israeli Committee whose members would include major political figures as well as leaders of the economy, intellectuals and educators. The role of such a body would be to authorize and fund various programs to draw the two communities closer. Modern technology allows Jews in America to divide their lives between Israel and the United States by buying a second home in Israel, or at least through time-sharing initiatives. This should be encouraged. Similarly, such a body could encourage young Israelis to visit Jewish federations in the States so they could better understanding the US Jewish community. At the end of the day, various external factors will influence the size of the US Jewish community in the coming 25 years or so. We have no control over many of them. But Jewish leadership in Israel and the United States can play a major role in influencing the character of this community and its size. I am convinced that if they do so creatively, US Jewry need not be destined to shrink. The writer, an MK, is chairman of Meretz.