Responsum: On Levirate Marriage
Question: We have heard that a sister-in-law who falls before an apostate is not permitted to [re-]marry unless he [i.e., her brother-in-law] performs ḥalitsah for her, as he remains sanctified [i.e., a Jew]. Therefore, [in this case,] when the [dead] husband was an apostate, and his wife was forced to live with him, and he died in his state of apostasy without children, does she require ḥalitsah or levirate marriage from his brothers? Let our master instruct us.
Answer: It is certainly as you have heard and as you needed to know. When the husband was an apostate and she was forced to live with him, and he died in his state of apostasy without children—know that she definitely does not require levirate marriage, as the Torah states: He shall succeed in the name of his dead brother (Deuteronomy 25:6). But this is no brother! And since she is not bound for the purposes of levirate marriage, neither is she bound for the purposes of ḥalitsah, since she is required to declare: My brother-in-law refuses to raise up a name for his brother in Israel (Deuteronomy 25:7). But that brother was not subject to raising a name in Israel!
According to the letter of the law, then, she is exempt from ḥalitsah. But we accept that the “bond” [between the wife and her brother-in-law] exists by virtue of biblical law, and we accept that the original marriage creates the bond, and they sent [an opinion] from the holy academy [saying] that, as a stringency, ḥalitsah is required. Therefore, if any case comes before you, the brother-in-law should perform ḥalitsah for her, and by virtue of that she will become free to remarry.
Published in: The Posen Library of Jewish Culture and Civilization, vol. 3: Encountering Christianity and Islam.