Q. Is a person who has left Judaism still Jewish?
A. The general principle is, “Even though one has sinned, he is a Jew” (Sanhedrin 44a). The Talmud quotes a saying, “A myrtle, though it stands among reeds, is still a myrtle”. Thus such a person is obliged to give his wife a gett if their marriage breaks down.
But there are limits to this recognition as a Jew. Someone who has joined another faith may not be accorded synagogal honours, such as being called to the Torah. Nor, if a kohen, may he duchan and bless the congregation.
After the Brother Daniel case in Israel, the Knesset amended the Law of Return to deny automatic recognition as a Jew to a person who has joined another religion. But since we believe in repentance, any person who finds his way back to Judaism is welcome. Some say it is as if he has been trying to hide from God and has found that in the end this can not be done.