There is no end to the conundrums involved in defining what it means to be a Jew.  Must a Jew be someone who believes in the Jewish religion, in the way a Christian believes in Christianity or a Muslim in Islam?  That can't be the case, since many devoted Jews are atheists.  Is a Jew necessarily someone who acknowledges membership in a Jewish ethnic group, people, or nation?  That definition would exclude people who believe in Judaism but feel little kinship with other believers, and it would read out Jews who are anti-Zionist.  Should "Jewish" be seen as a cultural identity?  If so, it would cover people who are stirred to their souls by Fiddler on the Roof, live on the Upper West Side of Manhattan, enjoy Jewish food, appreciate Jewish...