(Another case is described in Kesuvos 3a: a person gives a Get to his wife
on condition that he does not return, and then circumstances beyond his
control prevent him from returning. Even though the Get is not a valid Get
mid'Oraisa (since a fulfillment of a condition against one's will is not
considered as though one fulfilled the condition), the Rabanan instituted
that the Get does take effect (for the reasons that the Gemara describes).)
How does this mechanism of uprooting the Kidushin work? When the Rabanan
uproot the Kidushin, is it considered as though the couple were never
married? If so, it should be possible to remove the status of a Mamzer in a
situation where a married woman committed adultery or was raped and had a
child from the union; although the child is a Mamzer, it should be possible
to make the child legitimate by having the Kidushin uprooted retroactively
(such as by sending her a Get with a Shali'ach and then annulling the Get)!
Similarly, a man could save his wife from being punished with Misah, where
she committed adultery, in this manner as well! (TOSFOS DH v'Afke'inhu)
In addition, the PNEI YEHOSHUA points out that if the Rabanan uproot the
Kidushin retroactively, then when the brother of the husband later marries
the woman (who is Asur to him as "Eshes Achiv"), the Kidushin should take
effect mid'Oraisa (and she should require a Get if she wants to leave him)
since she is not his "Eshes Ach!" Is that indeed the Halachah?
Another question is that if the Rabanan are able to remove Kidushin in such
a manner, then why do they not use it in a broader context -- such as to
permit Agunos to remarry? For example, in a case where a husband drowns in
the sea ("Mayim sh'Ein Lahem Sof") and there is no positive testimony that
he is dead, the Halachah is that his wife may never remarry. The Rabanan
should permit her to remarry by exercising their authority to uproot the
Kidushin!
(a) TOSFOS says that it is true that where the Rabanan uproot the Kidushin,
a child who is a Mamzer due to the Kidushin becomes legitimate, and the
woman becomes exempt from punishment for committing adultery (and,
presumably, if she marries the brother of her husband, the Kidushin with him
will take effect). However, a person cannot take advantage of this right of
the Rabanan in order to intentionally correct the status of a Mamzer. In
such a case -- where a man intentionally sends a Get to his wife with a
Shali'ach and then annuls the Get in order to save his wife from punishment
or to make his wife's illegitimate children legitimate -- the Rabanan do
*not* uproot the Kidushin. They only uproot the Kidushin when a man annuls
the Get innocently, with no ulterior motives.
As for why the Rabanan do not exercise their authority to uproot Kidushin in
order to permit Agunos to remarry, the RAMBAN and RASHBA explain that the
Rabanan exercise this power only where there was some form of Get that was
already given. Even though the Get itself is not valid, the Rabanan uproot
the Kidushin based on the giving of the Get.
This also seems to be the intention of RASHI here who repeatedly writes that
the Rabanan uproot the Kidushin "when a Get is given." (Rashi in Shabbos
(155b) writes that the reason the Rabanan permitted a woman to remarry based
on the testimony of a single witness is because of the principle of
"Afke'inhu." Here, Rashi explains why the Rabanan do not apply "Afke'inhu"
to permit Agunos in other situations. Rashi is explaining that in the case
of a single witness who testifies that the husband died, there is at least
some sort of testimony that he died, and thus there is a foothold for the
Rabanan to uproot the Kidushin. According to Rashi, wherever there is some
form of Get or some form of testimony of death, the Rabanan can apply
"Afke'inhu.")
(b) The RAMBAN and RE'AH write that although the Rabanan uprooted the
Kidushin d'Oraisa, they nevertheless established in its place a Kidushin
d'Rabanan. Therefore, the child born to the woman from another man will
still be a Mamzer d'Rabanan, and the relatives of the husband will be
prohibited to the woman mid'Rabanan. Similarly, she will be prohibited
mid'Rabanan to marry a Kohen.
(c) The Rishonim here (RAMBAN, RASHBA) and here and in Kesuvos (3a) quote
the RASHBAM (see also PNEI YEHOSHUA here) who suggests that when a condition
of the Get is fulfilled against the husband's will, and when a husband
annuls a Get after having sent it with a Shali'ach, the Kidushin is not
uprooted retroactively, but rather it is uprooted from now on, "mi'Kan
ul'Haba." (See also SHITAH MEKUBETZES in Kesuvos who quotes the Rashbam as
found in a marginal note in a manuscript of Rashi's commentary.)
The Rashbam explains that the Gemara means that the Rabanan have the right
to uproot the Kidushin retroactively, and if they do so, all of the Be'ilos
retroactively become Be'ilos of Z'nus. Since nobody wants his Be'ilos to
become Be'ilos Z'nus, when he gives a Get with a condition, he has in mind
that even if the condition is fulfilled later against his will, he still
wants the Get to be valid. Similarly, when a man annuls a Get, since he
knows that the Rabanan will make his Be'ilos into Be'ilos Z'nus if the Get
is annulled, he does not really want to annul the Get.
The Ramban asks that according to this, in a case where a woman is only
betrothed (with Erusin), and her husband gives her a Get on condition or
annuls a Get that he sent with a Shali'ach, the Kidushin *should* be
uprooted retroactively, since the man has not had relations with his wife
and thus has no fear that his Be'ilos will be made into Be'ilos Z'nus! The
Ramban answers that even though there was no Be'ilah, the husband has in
mind that the Get should take effect even if the condition is fulfilled
b'Ones, because he knows that if he does not want it to work, it will not
gain anything for him (since the Kidushin will still be uprooted against his
will). Therefore, he intends for the Get to take effect no matter what.
(d) RASHI cites a fourth explanation in the name of "my teachers." This
explanation is actually found in PERUSH RABEINU GERSHOM in Bava Basra (48b).
He explains that all Kidushin nowadays is only mid'Rabanan in any case, and
that is why the Rabanan are able to uproot it from now on. Rabeinu Gershom
asserts that Kidushei Kesef (and Kidushei Shtar) are mid'Rabanan, while
Kidushei Bi'ah -- which is mid'Oraisa -- cannot make a Kidushin d'Oraisa
nowadays since the Rabanan prohibited being Mekadesh a woman with Bi'ah
(Kidushin 12b). The Rabanan went further and said that since everyone is
"Mekadesh Al Da'as d'Rabanan," all Kidushei Bi'ah does not work mid'Oraisa
nowadays (and it only makes a Kidushin d'Rabanan).
(Once the Rabanan instituted that one can be Mekadesh a woman with Kidushei
Kesef, it became a an act of effrontery to be Mekadesh a woman with Bi'ah.
Therefore, when the Rabanan instituted Kidushei Kesef, they also instituted
that a person may not be Mekadesh with Bi'ah and they annulled that form of
Kidushin, based on the premise that when a person gets married, he does so
according to the will of the Rabanan.)
Rashi and the other Rishonim ask strong questions on the explanation of
Rabeinu Gershom.
1. First, how can he say that Kidushei Kesef (and Kidushei Shtar) are
mid'Rabanan, when Kidushei Kesef is derived from a Gezeirah Shavah (Kidushin
2a) and is thus clearly d'Oraisa?
Apparently, Rabeinu Gershom learns that this Gezeirah Shavah is not an
actual Gezeirah Shavah mid'Oraisa, but is only an Asmachta. (The same
applies to Kidushei Shtar, which is learned by comparing it to a Get
(Kidushin 9b). Rabeinu Gershom understands that comparison to be only an
Asmachta.)
2. Second, Rashi asks that we know that a Ne'arah Me'urasah is defined as a
woman who was assumed to be a Besulah at the time of the Nesu'in, but was
found to have had relations with another man while she was an Arusah. The
Torah punishes such a woman with Sekilah. How can the Torah consider her to
be a Besulah at the time of Nesu'in if, mid'Oraisa, there is no such thing
as Kidushei Kesef or Kidushei Shtar? The only way she could have become an
Arusah, mid'Oraisa, is through Kidushei Bi'ah, and thus it is not possible
for there to be a case of Ne'arah Me'urasah!
Rabeinu Gershom apparently was not bothered by this question, because we
could say that the Kidushin was done with a Bi'ah *she'Lo k'Darkah*. Such a
Bi'ah serves to make the woman an Arusah, but it does not make her a Be'ulah
and she remains a Besulah. (See in full the Gemara in Kidushin 9b. Even
though the Gemara there rejects this possibility, perhaps Rabeinu Gershom
understands that the Sugyos are arguing.)
3. Third, Rashi in Kesuvos asks that according to Rabeinu Gershom, a woman
who gets married with Kidushei Bi'ah should be permitted to leave her
husband without a Get. Rabeinu Gershom apparently learned that although the
Rabanan removed the Kidushin d'Oraisa, they did substitute in its place a
Kidushin d'Rabanan which does requires a Get.
4. Fourth, Rashi here asks how the Rabanan can annul a Kidushin that was
made through Bi'ah simply by prohibiting it mid'Rabanan? Why should this
prohibition prevent the Kidushin from taking effect?
Rabeinu Gershom apparently learns that it is possible for the Rabanan to
make a prohibition that prevents something from taking effect mid'Oraisa, as
we find in TOSFOS in Sukah (3a) with regard to a person who sits in a Sukah
in a manner which the Rabanan prohibited. In the case of performing Kidushin
with Bi'ah, it is possible that the way the Rabanan prevented the Kidushin
from taking effect is as follows: The reason the Bi'ah accomplishes Kidushin
is because it demonstrates Ishus -- conducting themselves in the manner of
husband and wife. By conducting themselves as though they are married, the
marriage is effected. But once the Rabanan prohibited Kidushei Bi'ah, the
Bi'ah is an act of Z'nus and not an act of Ishus, and since it does not
demonstrate the conduct of husband and wife, it cannot effect Kidushin.