If the reason for "get" working at all in a case of zika is that the Rabbanan were gozer since asi l'miv'al achar chalitza if we don't take the "get" seriously...then why not say that R. Gamliel says ain get achar get because if we take the first get seriously then there is no need to take the second one seriously anyway....additionally, how would the Rabbanan answer that?
There should be no need to be gozer on the second get.
Hope that makes sense. Please let me know your thoughts.
Jason Schmidt, Clifton, NJ, US
1) It seems to me that if it would only be for the reason of "Asi l'Miv'al Achar Chalitzah" (50b), this would not be sufficient to make it a proper serious Get, but is merely a Gezeirah that if the Get would not work then people would say that Chalitzah does not work either. But there is another reason why "Ein Get Achar Get": since giving the first Get means he did not build up his brother's house, none of the brothers can now build up any of the deceased brother's house, with any of his wives.
2) The Rabanan hold that the first Get does not complete everything because even after the first Get, Chalitzah is still required. So the dispute between Raban Gamliel and the Rabanan seems to be that Raban Gamliel says that the first Get finishes everything since he no longer can build up the house, while the Rabanan say that it does not finish everything since Chalitzah is still needed.
3) My source for what I wrote above (in 1) is the Bartenura on the Mishnah. From Rashi on the Mishnah, however, we learn a different Pshat. There is a doubt, according to Raban Gamliel, about whether the first Get works. If it does work, then the Zikah is totally cut off and both widows are now completely exempt from anything to do with Yibum, so the second Get is meaningless since it is equivalent to giving a Get to a woman with whom one has no connection. If the first Get does not work, then the second Get is no better than the first and will also not work.
4) The way the Rabanan learn is very different. They do not have a doubt about whether it works mid'Oraisa like Raban Gamliel does. They say that mid'Oraisa it certainly does not work but mid'Rabanan it does work because of Asi l'Miv'al Achar Chalitzah.
To summarize, one cannot compare the opinions of the Rabanan and Raban Gamliel. The Rabanan discuss a Get which is invalid only mid'Rabanan.
This is a difficult Sugya and for the moment I do not think I can say that I am really answering your very good questions, Yeshayahu, but merely suggesting one or two ideas, and I hope, bs'd, in the course of time to give a more thorough answer.
1) Rashi (50b, at the beginning of the Gemara, DH Aval Get) writes that when one gives a Get to a Yevamah, this creates a Torah prohibition of "he shall not build" if one would afterwards do Yibum. So even though the Get is not d'Oraisa, it does effectively terminate the possibility of doing Yibum d'Oaraisa.
2) The Keren Orah (51a, DH Gemara Mai Ta'ama d'Raban Gamliel) writes that according to the Talmud Yerushalmi, the Get does not "Patur" the Yevamah but it is "Docheh" here; it does not exempt her, but it does push her off. The Keren Orah compares this to the Gemara below (52b) where Rebbi Akiva learns from a verse that if a Yavam gives a Get to the Yevamah she becomes forbidden to him forever. We see that a Get can "push off" a Yevamah mid'Oraisa.
3) After having looked again at the Sugya, it seems to me that the Gemara knew that one has to say that there is a big difference between Raban Gamliel and the Chachamim, simply because they appear to be totally opposite in the Mishnah. Raban Gamliel says that there is no Get after a Get, while the Chachomim say that there is a Get after a Get. So if we were to try to make Raban Gamliel and the Chachamim to be of the same view, that would not follow the simple reading of the Mishnah.
4) I found, bs'd, that the Sefer Yosef Lekach (by Rav Yosef Raf zt'l 1874-1918), at the beginning of 51a, writes that Rava, who is in doubt there about whether -- according to Raban Gamliel -- the Get pushes off or not -- is actually in doubt about whether it is Docheh mid'Oraisa or not. So the Yosef Lekach was Mechaven to the Keren Orah cited above, who wrote that according to the Talmud Yerushalmi the Get can push off mid'Oraisa. However, the Yosef Lekach strengthens this possibility by pointing out that the simple reading of the first line of the Gemara on 51a is that the doubt of Raban Gamliel is at a d'Oraisa level.
5) I also found, bs'd, that the Yefeh Einayim (printed at the back of the Gemara) on 51a, who generally cites the Talmud Yerushalmi, writes here that the Yerushalmi wanted to say that Rebbi Shimon holds that Ma'amar makes a complete Kinyan (see Tosfos to 29a, DH Lo Teima, and Chazon Ish, EH 132:6). If Rebbi Shimon holds that Ma'amar is d'Oraisa, then it is also possible that Raban Gamliel holds that a Get has an effect mid'Oraisa.
These are all big Chidushim, but even if we follow the majority of Mefarshim and say that Raban Gamliel does not hold that the Get is mid'Oraisa, at any rate it makes sense to say that it is not simply a Gezeirah and has a more powerful origin than what Chachamim maintain.
6) I should add that the Yosef Lekach (51a, DH v'Od Y'L, p. 73 of the Sefer) also cites the Gemara below (52b), as did the Keren Orah, where Rebbi Akiva learnes from Devarim 24:4 that if one gives a Get to the Yevamah she becomes forbidden to him forever. Again, the Yosef Lekach adds a new idea and suggests that the doubt of Raban Gamliel (beginning of 51a) was whether this Derashah of Rebbi Akiva was an Asmachta or a full Derashah.
(There is a certain difficulty with this Pshat - namely, the Gemara below, towards the end of 121a, which states that Rebbi Akiva sat before Raban Gamliel, which suggests that Rebbi Akiva was a Talmid of Raban Gamliel. However, we do sometimes find in the Gemara that earlier scholars knew what later scholars also cited.)
I would add that even if we say that Rebbi Akiva's Derashah is only an Asmachta, still an Asmachta is stronger than the ordinary Takanah d'Rabanan, so we can still say that the Get, according to Raban Gamliel, is stronger than what the Chachamim maintain.
7) In addition, I cannot understand the Reshimos Shi'urim. He mentions physical doubts (i.e., an Androginus is a person for whom there is a physical doubt about whether the person is a male or female; similarly, regarding twilight, there is a physical doubt about whether it is day or night). The Get of the Yevamah is not a physical doubt; it is purely a doubt in Halachah. How can the Reshimos Shi'urim compare the Androginus and Bein ha'Shemashos to the Get of the Yevamah?