From Yossi Beilin's book, His Brother's Keeper:
It is simply unimaginable that in the 21st Century, a time in which most of world Jewry is not religious, we should continue to grant certain religious establishments the right to define "who is a Jew". While it is true that significant differences between the streams of Judaism exist, it is also true that all of them retain an exclusive character. All are cautious regarding their number of conversions and all insist that the transition into the Jewish people be done through a process that is solely religious.
Many cases of conversion involve an agreed-upon lie. Most converts are in fact converting in order to marry a Jewish partner. They must convince the rabbis that their act is based on belief and that they will keep the commandments as Jews, while both the rabbis and most of the converts know that this is not the case. Those who do not want to lie choose not to convert, even if in some spiritual sense they identify with the Jewish people and heritage.
Were Judaism only a religion, no one would question the rabbinic monopoly, and the argument would merely revolve around recognizing the various Jewish streams. However, since Judaism is also "something more", there is no reason for rabbis to only lead people to this "something more" via a religious route within a religious monopoly. Judaism is also a nation, and an existential culture. Many Jews, maybe most Jews, are either atheists or agnostics, yet no one questions their Jewishness. Why is someone like me allowed to be an agnostic Jew while a convert to Judaism is not? Why must a non-Jewish atheist or agnostic go to a rabbi in order to become a Jewish atheist or agnostic?
In Israel, there are now hundreds of thousands of people, mostly family members of olim, new immigrants, from the former Soviet Union, who are not inclined to undergo a religious conversion but still live their lives as Jews. This scenario is most poignantly brought to our attention when a soldier, who is also a new immigrant, is killed in action, and it transpires that his mother is not defined as a Jew, and so he may not be buried in a Jewish cemetery.
We must give these people, those who wish to be identified as Jews, the right to join the Jewish people on the basis of their own self-definition. I envision a situation where a non-Jew - who does not claim membership in another religion - turns to the local Jewish community and asks to be registered as a community member. The community would ask for references from two Jewish community members, as is customary upon joining certain movements or clubs. Once the community is convinced that the reasons for joining are pure and that the motivation is straightforward, it would register this new Jew within its ranks without providing her or him with a religious ceremony. If the new member later chooses to marry within a Reform context, the Reform movement would require a Reform conversion; similarly the Conservative and Orthodox movements. The new Jew would then decide whether to undergo that procedure. From the standpoint of the Jewish community, however, the individual would be considered a Jew based on self-definition.
As the secular concept crystallizes - and there are fascinating signs that such a crystallization is currently occurring - secular Judaism will take its place as a stream of Judaism alongside the current three or four religious streams. This stream, which includes potentially huge numbers, could develop its own secular conversion procedure. In addition to the self-definition that I described earlier, there could be a secular conversion that would constitute acceptance into secular Judaism, both in the Diaspora and in Israel.
If this approach is adopted, the exclusive concept of conversion would be exchanged for an inclusive one, one that would open doors that are currently closed. I do not believe that it is possible to affect the shrinking size of the Jewish people through a change in definition alone. Nonetheless, there is no doubt that there are fewer Jews because the religious establishment does not recognize everyone who sees herself or himself as Jewish.
There is no reason in the 21st Century for the religious establishments to exclusively define the number of Jews. If the self-defining approach is accepted - and this would surely entail a significant psychological readjustment - we will become both a larger and more attractive nation. Clearly, the change would require very serious discussion between Israeli and Diaspora Jews regarding the precise manner in which non-Jews would join the Jewish people. As well, we would need to guard against a cynical exploitation of our newly opened doors. To this end, we would need to come together as one. Such a "Beit Yisrael", "House of Israel", would hopefully be able to arrive at practical recommendations, and allow us to realize the necessary changes