BIROBIDZHAN, Russia — Andrey Zasorin, the spiritual leader of the old synagogue here in the capital of Russia’s Jewish Autonomous Region, is a born-again Jew who found God after 23 years in prison for robbery. Even then, he returned to Judaism only after flirting with the Russian Orthodox and Pentecostal churches.

Yelena Sarashevskaya, the editor of the local paper, Birobidzhaner Shtern, which still publishes two or three pages a week in Yiddish, is not Jewish. She is a descendant of Cossacks, but married a Jew and learned to read and write Yiddish in college.

Identity is a complex issue in the quixotic Jewish homeland established by Stalin here in the mosquito-infested swampland of Russia’s Far East, some 20 years before the founding of Israel. While the big menorah standing outside the railroad station, the Yiddish street signs and ubiquitous Stars of David give Birobidzhan the veneer of a Jewish Disneyland, the city often seems to have the religious authenticity of a pizza bagel with pepperoni.

Because of this gap between the city’s spirit and its spirituality — not to mention the dwindling number of people who actually call themselves Jews — commentators have been predicting the Jewish Autonomous Region’s demise for decades. But whether on the Upper East Side, or in Jerusalem, or on this last patch of Siberia along the Chinese border, Jewish is as Jewish does. And when it comes to the so-called Soviet Zion, Ms. Sarashevskaya, for one, is sick of the snickering.