Rambam
Rabbi Yitzchok Etshalom
Talmud Torah 7:10
10. If someone doesn't know who declared the Nidui on him, he may
go to the Nasi (head of the Court), who will lift the ban.
Q1: May the Nasi lift the ban even if the Menudeh knows who
banned him, but doesn't want to go to him? Or that person (as in
the previous Halakha) left town?
YE: From the sugya in Mo'ed Kattan (17a), it seems that the Nasi
may only operate in this way when the Menudeh cannot identify the
one who placed him in Nidui. It does not necessarily follow that
if the person was known but unavailable or died, that the Nasi
may lift the ban - that may require a regular Beit-Din (as in MT
Talmud Torah 6:12).
Q2: What is the function of the Nasi here - as representative
of the court or it's highest officer?
YE: Since we learned that if the Nasi declares Nidui, all Jews
mujst respect it - but not the inverse - (MT Talmud Torah 6:13) -
it follows that it is the Nasi's office which stands on top of
the "Nidui hierarchy" - due to the Beit-Din and Torah-honor
nature of Nidui (as mentioned above). Here, the Nasi may lift
the ban because he is the highest officer of the court. Since
the hierarchy of the court climaxes with the Nasi, any
Nidui-related issue will become subject to his approval or lack
thereof.
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