It is time to rethink our understanding of how Judaism is passed from one generation to the next
In a recent essay decrying the Reform rabbis' decision on intermarriage--a decision I applaud, by the way--Elliott Abrams comments that "the Reform movement unilaterally abrogated 5,000 years of Jewish law and practice by throwing matrilineal descent out the window. Now American Jews can't even agree on who is a Jew: someone born of a Jewish mother, as had always been the case, or someone born of a Jewish father and gentile mother as well?"
The basic complaint is heard frequently in Conservative and Orthodox circles, namely that the Reform movement has split the Jewish people, because neither the Conservative nor Orthodox branches of Judaism accept patrilineal descent--the idea that Judaism is passed through either parent, not just a mother. It is a fine polemic, but I think it ignores the underlying realities that, to their credit, Reform rabbis are trying to address. I wish that other parts of the Jewish world would also seriously address the issue instead of simply attacking Reform Judaism for facing up to facts.
It is true that matrilineal descent is the rabbinic norm. It's not 5,000 years old, however. The ruling really dates back to the time of the restoration of the Second Temple, to the Book of Ezra--which is more like 2,500 years ago. At that time, with the Jewish people facing the difficult task of rebuilding the Temple, Ezra annulled marriages between Israelites and "foreign wives." Subsequent rabbinic thought builds on this foundation, and that leads us to today.
But if we are talking about tradition, patrilineal descent in Judaism is actually much older than matrilineal descent. Consider for instance that on Friday night in Jewish homes, female children are blessed to be like the matriarchs, while the male children are blessed to be like "Manasseh and Ephraim." This recalls the extraordinary blessing (with crossed hands) that Jacob gives to Joseph's sons.
Joseph lived in Egypt, married an Egyptian woman, and had these two sons. They can only be Jewish through Joseph's side--hence they are Jewish by patrilineal descent, not matrilineal descent. (Perhaps there was a convocation of Reform Rabbis in Egypt at the time?) My point is that while certainly matrilineal descent has been the norm in rabbinic Judaism, it has not "always been the case," as some like to believe. Therefore, in a changing circumstance one can certainly find a biblical basis for patrilineal descent. It's in the very blessing repeated in Jewish homes every week, binding one generation to the next.