The bill could give the chief rabbinate, the religious authority in Israel run by ultra-Orthodox Jews, the power to decide which conversions are accepted, overturning an Israeli Supreme Court decision that ensures eligibility for Israeli citizenship for Jews converted by rabbis from all branches of Judaism.

Representatives of the Reform and Conservative movements, which have been battling for years for more rights in Israel, saw the committee vote as a threat to their efforts to strengthen their legitimacy in Israel. The chief rabbinate already holds a monopoly on such rituals as marriage and divorce.

It sets us back 20 years in terms of the advances that were made, said Rabbi Steven Wernick, executive vice president of the United Synagogue of Conservative Judaism, an umbrella organization of Conservative Jewish congregations in the United States, who spoke by telephone during a visit to Jerusalem. The practical implication of this bill is one that we are very, very concerned about and angry about.

The bill delegitimizes most of North American Jewry and brings back the question of who has the authority to determine someone's Jewish identity, Wernick added, noting that 85 percent of American Jewry is affiliated with non-Orthodox branches of Judaism.