Since conversion to Judaism can have a negative impact on the spiritual purity of the Jewish people, only the greatest halachic authorities of the haredi rabbinical establishment can decide on this, the Chief Rabbinate's High Rabbinical Court ruled recently. "Any decisions by Rabbinical Conversion Courts or rabbinic marriage registrars that are not in accordance with the opinion of the greatest halachic authorities of the generation hurt the purity of Jewish people," wrote Rabbi Avraham Sherman, head of the High Rabbinical Court. "There is a real danger that gentiles will be allowed to enter the Jewish community. Anyone who did not embrace an Orthodox lifestyle at the time of conversion is a gentile and if this person is female all of her children are gentiles as well," Sherman continued. The High Court also ruled that the high proportion of potential converts to Judaism who are not sincere about embracing Orthodoxy was an insurmountable challenge that made it impossible to rely on any rabbinical conversion court - haredi or modern Orthodox - to perform a kosher conversion. Sherman stated explicitly that a conversion has no validity unless the convert proves he or she has embraced an Orthodox lifestyle. Anything less is unacceptable. According to the decision, the Jewishness of converts can in theory be revoked at any time, no matter how long ago the conversion took place and no matter which Rabbinical Conversion Court performed the conversion. Conversions can and must be revoked if, for instance, after the conversion process the convert admits that he or she did not adhere to the Orthodox halachic restrictions governing Shabbat, kashrut or other Jewish laws. To preserve the purity of the Jewish people, every convert must be scrutinized on an individual basis by rabbinic marriage registrars and rabbinic courts before he or she is permitted to marry or divorce, Sherman wrote in a 34-page rabbinical opinion handed down within the framework of an appeal case on May 10. Rabbi David Stav, a senior member of Tzohar Rabbis, an organization of moderate Orthodox Zionist rabbis, called Sherman's comments scandalous. "Sherman is committing the biblical sin of insulting the convert," Stav, who is chief rabbi of Shoham, said on Tuesday. "A group of haredi functionaries are willing to place under suspicion thousands of converts just because they want to wage a political power struggle. "When [former Chief Ashkenazi] Rabbi Shlomo Goren wanted to annul a conversion the haredi community attacked him, claiming it was impossible. Now they have changed their minds according to political interests." Stav was referring to the Langer case in which Goren annulled the conversion of a woman's husband to prevent her children from being considered mamzerim (the result of an illicit sexual act which bars them from marrying a Jew). Stav said haredi activists were using the conversion issue to shore up their rabbinical clout vis-Ã -vis the Orthodox Zionist establishment. Stav, who serves as the Chief Rabbinate's marriage registrar in his town, said he accepts all converts converted by a legitimate Rabbinical Conversion Court. "I do so whether the conversion was performed by the Chief Rabbinate or by a haredi conversion court, although I must say that converts who come out of haredi conversion courts are usually less serious than those converted by the Chief Rabbinate," he said. A three-man panel of rabbinical judges made up of Sherman, Rabbi Hagai Izerer and Rabbi Zion Algrabli rejected the halachic principle that a rabbinic court decision, once handed down, was irreversible. Sherman was responding to a Tel Aviv Rabbinical Court ruling in a divorce case that involved a woman who had converted to Judaism. The Tel Aviv Rabbinical Court refused to accept claims by the husband that his wife's conversion was invalid, because, he claimed, the wife had paid a NIS 10,000 bribe to the court that performed her conversion. The Tel Aviv court ruled instead that it did not have the power to overturn a decision - in this case a conversion - by another court since the underlying assumption is that rabbinical courts know what they are doing. However, Sherman rejected the Tel Aviv court's argument despite the fact that it was based on an accepted halachic principle. He ruled that the Jewish status of the woman and her children must be lifted until the Tel Aviv court could ascertain whether the claims against the validity of her conversion could be refuted. Sherman said in a telephone interview with The Jerusalem Post that there was nothing new in his decision and that he was basing himself on the opinions of this generation's greatest halachic scholars, both living and deceased. Sherman quoted from declarations published in recent decades by leading haredi halachic authorities such as Rabbi Yosef Shalom Elyashiv, considered to be the single most important living halachic decisor for haredi Ashkenazi Jewry. Sherman also quoted deceased authorities such as Rabbi Shlomo Zalman Ohrbach, Rabbi Ya'acov Yisrael Kanyevsky and Rabbi Elazar Menachem Man Shach. In one declaration, signed by Shach, Kanyevsky, Ohrbach and Elyashiv and dating from the summer of 1984, the rabbis warned that "since there has been a rise in the number of converts who have been accepted as Jews and that it has become known that a large percentage of them had no intention of accepting upon themselves the burden of the commandments at the time of conversion... We are warning that there is a prohibition to accept converts without first being sure that they are interested in accepting upon themselves all the commandments." Sherman and the other rabbinical judges in May concluded from this declaration and others that every conversion must be considered suspect, "whether it was performed by the Edah Haredit or some other rabbinic court that is recognized more or recognized less, when a person presents a conversion certificate issued by a rabbinic court and that person's appearance is far from the appearance of an observant Jew or that person comes from a place that has no observant community." Sherman said this was especially true in the case that came before the Tel Aviv Rabbinic Court, which dealt with the Jewishness of the wife and her children.