Many Jews stayed in ghettos because they had no choice, not out of zeal. The current assimilation amounts to purifying blood-letting: the bad blood will go away. We need fresh blood. Gentile spouses who identify themselves with Am Israel and send their children to the IDF are fine Jews.
The Torah repeatedly emphasizes that Jewish forefather are not firstborn in their families. Why would the Torah deny the chosen people the rights of firstborn? One explanation is the dissociation from Cain, a firstborn who slew his brother. Or, refusing Jews the status of firstborn hints at the fact that many of them were actually of Egyptian origin and joined us during the Exodus. The biblical account of Jewish life in Egypt contains two distinct strains: the extreme suffering of the slaves and the affluent life which they wanted to return to from the Sinai. In the Book of Exodus, Levites have Egyptian rather than Hebrew names. The Holiness part of Leviticus and fragments in the other books substitute new meaning for the pagan rites Hebrews were accustomed to. The Torah remains critical of Jews: they constantly violate the commandments and fall into idolatry. The priestly group of Levites seems to assimilate a relatively huge number of aliens into Jewishness. We, too, should concentrate on maintaining Jewishness, and then the issue of Jewish lineage would become moot.

Jewishness is very different in Israel and the Diaspora. In Israel, less-than-full Jews who live in the Jewish state and fight for it have to all practical purposes joined the Jewish nation, no less than Ruth did. For them, even nominal (reformist) or de facto conversion (such as Ruth’s) suffices. In the Diaspora, Jewish self-identification is only actionable and demonstrable in religion. Consequently, Jewish conversions in the Diaspora cannot be de facto, and have to be both religious and substantial; the latter criterion excludes Reform conversions, which require nothing from applicants in their daily lives.
Those Jews who wish to marry Gentiles without proper conversion in the expectation of their Jewish behavior cannot be prevented from doing so. The free market provides a solution. If they believe their spouse is Jewish after a Reform conversion or just by virtue of her having read Karl Marx, then their children must also believe themselves Jewish and seek a similarly Jewish spouse. In effect, the children are marketing themselves to other Jews. If the offspring of such a semi-Jewish parent convinces the prospective Jewish spouse of his own Jewishness, so be it. If not, he will marry a Gentile and extinguish that Jewish line. In a matter of generations, the “spousal market” would distill the demanded Jewish traits—a degree of Shabbat observance and basic kashrut, and perhaps maybe something else. The semi-Jewish families who identify themselves with Jews for three or four generations can safely be regarded as Jewish.

It would be perfect if all Jews observed Judaism, but that’s not the reality. A strictly halachic interpretation of Jewishness is counter-intuitive as it considers the Peace Now members Jewish, which they are not by any measure. If most halachic Jews don’t observe Judaism, it is unreasonable to set Judaic observance as a criterion of conversion or allegiance. A non-observant person with a Jewish father is no less Jewish than a non-observant person with a Jewish mother. It would be perfect for both to observe Judaism, but both remain Jewish even while non-observant as long as they retain at least a political allegiance to the Jewish nation.

Political allegiance can be set as the minimum standard of Jewishness. A person with a Jewish parent who practically shares in the life of Jewish people by living in Israel is a Jew. Religious observance would make him a good Jew, a proper Jew, but a Jew he is regardless of observance. In the Diaspora, political Jewishness does not exist because there is no specifically Jewish way of life besides Judaism. In the Diaspora, accordingly, the only criterion for Jewishness is religious.