Commentaire sur Nida 4:2

פירשו ללכת בדרכי ישראל הרי הן כישראליות – but undefined, they are like Cuthean women.

Introduction Today's mishnah deals with Sadducean women. The Sadducees were one of the main factions during the Second Temple period. They were the rivals of the Pharisees, the group that the rabbis considered themselves to be the descendents of. Truth be told, we don't know a lot about the Sadducees because they left no historical record. The only information we know about them was written either by Josephus, the New Testament or the rabbis. In addition, many scholars believe that the Dead Sea Sect Jews were a splinter Sadducean group, although this is far from certain.

ר' יוסי אומר לעולם הן כישראל – but undefined, they are like Israelite women. But the Halakha is not according to Rabbi Yossi.

The daughters of the Sadducees, so long as they are accustomed to walking in the paths of their fathers, are to be regarded as Samaritan women. If they left those paths to walk in the paths of Israel, they are to be regarded as Israelite women. The mishnah basically accepts Sadducean women but disqualifies their ancestry. If Sadducean women observe Sadducean halakhah then they must always be regarded as niddot (menstruants), just as are Samaritan women. They will always defile the things that they touch and it will always be prohibited for Jewish men to have relations with them. However, the mishnah gives them more of an opportunity to join the remainder (meaning Pharisaic/rabbinic) Jews than it did for Samaritan women. All they must do is leave the path of their ancestors and "walk in the paths of Israel" and they are to be considered as regular Israelite women. Clearly this means that they must observe halakhah as the rabbis determine it. We should note that in this mishnah "Samaritan" has become a code word for a genetic Jew who does not observe rabbinic halakhah. A Sadducean woman cannot be a Gentile because she is genetically Jewish. But when the mishnah wants to say that she is outside the rabbinic fold, it calls her a Samaritan.

Rabbi Yose says: they are always regarded as Israelite women unless they leave the paths of Israel to walk in the paths of their fathers. Rabbi Yose says that the a priori assumption about Sadducean women is that they have left the path of their fathers and act like (rabbinic) Jews. This is probably testimony to the weakness of the Sadducean faction after the destruction of the Temple. The Sadducees were more of a Temple-based group than the Pharisees and they don’t seem to have coped very well with the destruction of the Temple. In Rabbi Yose's time, a woman of Sadducean descent can be assumed to be observing rabbinic halakhah.