Sotah 7b - Mechikas Hashem

The minchas chinuch (mitzvah 437) discusses the possibility that if one were to erase the name of Hashem for a purpose and not "derech hashchasa" it may not be a violation of mechikas Hashem. Based on this approach he points out that the erasing of Hashem's name by a Sotah would not be a violation at all.

The gemara explains that prior to erasing Hashem's name in the water we try to convince her to admit, but after erasing Hashem's name in the water we try to convince her to drink. Rashi explains that prior to the erasing we take measures to prevent the erasing of Hashem's name and therefore try to scare her out of drinking. This would not contradict the approach of the minchas chinuch, because even according to the minchas chinuch, if we can prevent the erasing of Hashem's name then it would not be necessary to do so and therefore be derech hashchasa, so we try to get her to admit to avoid the erasure.

However, after the name is erased we convince her to drink. According to the Minchas Chinuch the rationale would be simple. If she would not drink, the name would have been erased for no reason at all, but if she would end up drinking then there would be a valid reason for erasing Hashem's name. Therefore we would try to convince her to drink to avoid a retroactive mechikas Hashem l'vatala (Hagahos Ya'avetz offers a slightly different approach, that we convince her to drink because the miracle of the sotah waters taking effect will be a kiddush Hashem to out weigh the chilul Hashem caused by the erasure). Yet, rashi does not explain like this. Rather, rashi implies that the issur of erasing Hashem's name was already violated and cannot be retroactively fixed even if it is done for a constructive purpose. Therefore rashi explains that the purpose in convincing her to drink would be to restore her relationship with her husband on the chance that she is truly innocent (because if she would not drink out of fear, or admit guilt out of fear she would remain assur to her husband forever).

Rashi seems to hold that even erasing Hashem's name for a constructive purpose is a violation (as the gemara implies in succah and sanhedrin when dovid learned a kal v'chomer from achitofel to permit the erasing of Hashem's name to stop the waters from rising).

Sotah 6a - Zechus, Eidim, Relations with Husband are Toleh

The gemara says that either witnesses overseas who are aware that she is guilty, or zechus, or having relations with her husband on the road are all viable possibilities as to why the Sotah waters would not kill her even if she is in fact guilty. R' Shimon rejects the notion of zechus being toleh, because it will cause people to mock the effectiveness of the water and claim that even tahor woman are guilty just that a zechus protected them from the waters taking effect, but nevertheless agrees that witnesses overseas and having relations on the road would prevent the waters from taking effect [but since they are uncommon, it won't lead to mocking the sotah waters and claiming that the innocent are in fact guilty (rashi and tosafos).

Tosafos (6b d.h. U'tehora) writes that immediately after she drinks the sotah waters she is permitted to her husband. The question is, why should she be permitted after drinking since it is still possible that she is guilty just that the sotah waters didn't take effect for one of the reasons mentioned above?

Meshech Chochma (Parshas Naso) quotes himself in the Ohr Sameach (Issurei Biah 18:10) where he explains that prior to drinking we have a 'raglayim l'davar', a strong indication that she is in fact guilty. The gemara 3a explains that this raglayim l'davar which is due to the fact that she has undergone kinuy and stirah, is the rationale for an individual eid to be believed on the tu'mah, rather than requiring 2 eidim. However, after drinking, although it is possible that she is guilty and one of the above mentioned reasons prevented the waters from taking effect, the raglayim l'davar no longer exists. The raglayim l'adavar is not batul due to the ineffectiveness of the water, becasue there can be other causes for their ineffectiveness; but the fact that she had the nerve to drink the waters knowing good and well that if she is guilty it may be an act of suicide, nullifies the raglayim l'davar of her guilt and we return her to her chezkas kashrus of innocence. This explains why after drinking she is permitted to her husband, because the raglayim l'davar indicating guilt is batul, and she returns to a chezkas kashrus.

Additionally, this would explain why Tosafos (6a d.h. vi'shebau) suggests that perhaps if an eid echad testifies that she commited adultery after she had already drunk from the sotah waters, he would not be believed to pasul her from teruma because the eid echad is only believed so long as the raglayim l'davar is still in force, but after she willingly drinks it is gone.

Now, this is where it gets difficult....

Tosafos (Nida 2a - also in Nazir) asks how we can learn from Sotah that safeik tu'mah in reshus hayachid is tamei, by sotah there is a raglayim l'davar indicating her guilt so it is not a safeik hashakul. Tosafos answers that the raglayim l'davar would only create a safeik of guilt, but from the Torah considering her a "vadai temeiah" (28a) which contradicts her chezkas kashrus, we derive a gezeiras hakasuv that safeik tu'mah in reshus hayachid is definitely tamei even against a chazaka. This only makes sense if we assume that the ragalyim l'davar of sotah would not destroy the chezkas kashrus and consider her vadai tamei, it would only create a safeik that she may be tamei. The source that the raglayim l'davar doesn't make her a vadai tamei, is because if it would, the indication of her drinking would not be strong enough to remove the raglayim l'davar, and therefore she should be assur even after drinking since one of the aforementioned reasons could be causing the sotah waters to be ineffective. From the fact that after drinking she is permitted to her husband, the willingness to drink must have removed the raglayim l'davar, which would only be possible if the raglayim l'davar itself only created a safeik and didn't establish her as a vadai tamei [and therefore the Torah declaring her tamei would be a gezeiras hakasuv and be a valid source for safeik tu'mah in reshus hayachid tamei, even when there isn't any raglayim l'davar].

Sotah 5b - Safeik Sotah

In Yevamos 11, the gemara says that a sotah vadai (witnesses confirming she committed adultery) would not fall to yibum and even exempt her tzarah from both yibum and chalitzah. This is derived from the fact that the Torah calls it "tum'ah" like arayos. Tosafos (Yevamos) asks, how then does our gemara ask that by a safeik sotah (a woman who received kinuy and stirah and her husband dies before she drinks) that she should be able to do yibum with the husbands brother - since she is a safeik sotah, there is a chance that she committed adultery and does not fall b'yibum, so misafeik we should not be matir her to do yibum?

R' Chaim (Chidushei HaGrach 6:19) explains that the gemara who considers a safeik sotah who had kinuy and stira to be assur m'safeik and even goes so far to say that we treat the safeik like a vadai (28a) is only a gezeiras hakasuv regarding the kinuy that it is strong enough to make the stirah that follows create an issur and even treat the safeik like a vadai. But in actuality she still has a chezkas heter and her status of safeik is not a real safeik hashakul, rather we assume she is innocent. Therefore, only regarding the effect of the kinuy and stirah that they create an issur, do we treat her as a true safeik and even like a vadai, but we don't truly suspect her of committing adultery and even as a safeik are not concerned that the label "tum'ah" applies to her, so without the limudim found in our gemara we would even permit yibum. With this R' Chaim explains the Rambam who paskens that the tzarah of a safeik sotah is allowed to even do yibum, because the special exemptions that we have in our gemara only apply to her, but regarding the tzarah we consider the safeik sotah innocent based on her chazaka, and even allow her tzarah to do yibum.

The Netziv (Meromei Sadeh) deals with this like a real safeik. His approach is that if we hold safeik d'oraysa l'chumra, we would not need a pasuk to assur a safeik sotah (because she is a safeik d'oraysa of being a vadai sotah). From the fact that we need a source to assur a safeik sotah from doing yibum, it is in effect a gezeiras hakasuv saying that she needs chalitzah b'toras vadai because we regard her as being zakuk to yibum, and therefore her tzara is also zekukah to yibum.

Sotah 3a - Hating Fellow Jews, Osek B'mitzva

1. The gemara says that we need a special pasuk to be matir a husband giving kinuy to his wife. Without a pasuk being matir it would be a violation of the issur "לא תשנא את אחיך בלבבך". Rashi (d.h. k'lfi) explains that this issur is not to do things that create machlokes, and giving kinuy to his wife will certainly incite her and cause machlokes (the Radal in the back of the gemara points out that even though the gemara says in pesachim that one is entitled to "hate" someone who does an aveira and there isn't a violation of hating him, that is only when they actually commited an aveira, to the exclusion of this case where he merely suspects her).

The Rambam writes in Hilchos Deios 6:5 - כל השונא אחד מישראל בלבו עובר בלא תעשה שנאמר "לא תשנא את אחיך בלבבך" ואין לוקין על לאו זה לפי שאין בו מעשה, ולא הזהירה תורה אלא על שנאה שבלב אבל המכה את חבירו והמחרפו אע"פ שאינו רשאי אינו עובר משום לא תשנא

The Rambam clearly holds that the issur of לא תשנא is only violated if he hides his anger, but inciting machlokes through kinuy would not be a violation. How is the Rambam going to work out this gemara which clearly says that it would be a violation?

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2. In my sefer Nasiach B'chukecha (pg. 66, note 16) I quoted R' Tzvi Pesach Frank in the name of R' Shmuel Salant that if a person is involved in a mitzvah that he originally was not obligated to do, but by becoming involved he is now obligated, since he is fulfilling a mitzvah we apply the p'tur of osek b'mitzvah patur min hamitzvah. Therefore, even though a Talmid Chacham doesn't have to return a lost object that is beneath his dignity, if he starts returning it he must continue and therefore we would apply the principal of o'sek b'mitzvah patur.... (which is against the nesivos 72:7).

From Tosafos (3a bottom) we see a much bigger chiddush. Tosafos (based on Maharsha) explains that according to the opinion that it is a mitzvah for a kohen to be metamei for kerovim, then even if there are others available to bury the person so that he is not obligated to become tamei, if he chooses to involve himself in the burial it is not regarded merely as a reshus, but rather regarded as a mitzvah to the point that he will be exempt from another mitzvah that comes his way. We see from here that even a mitzvah which is just a kiyum mitzvah and not an obligation is strong enough to be considered osek b'mitzvah and exempt him from another mitzvah that comes his way.

Sotah 2a - Zivugin are difficult like krias yam suf

Rashi explains that the statement of the gemara that it is difficult to make zivugin like krias yam suf, is not refering to the bringing together a man and woman, rather it is refering to the ability to make sure that each spouse receives one who is l'fi ma'asav. The gemara then asks from the statement of R' Yehuda in the name of Rav that a spouse is determined for every man (tosafos) already 40 days prior to yetziras havlad. The maharsha points out that this question can simply be on the statement immediatley preceeding which is the statement of "קשה זיווגין כקריעת ים סוף" which implies that Hashem כביכול has a difficult time, yet we find that it is determined before he is even born which implies that it is accomplished without any difficulty. However, Rashi explains the question differently. The question is really on the fact that zivugin are done according to a persons accomplishments (צדיק או רשע), and asks that we find that Hashem sets up shidduchim 40 days prior to yetziras h'vlad before it is determined whether he is a tzadik or rasha. Rashi avoids the maharsha's question, because rashi explains that the statement of קשה זיווגין כקריעת ים סוף is also predicated on אין מזווגין לאדם אלא לפי מעשיו.

This approach of Rashi forces him to deal with the paradox of the Rambam that G-d knows the future, yet one has free choice to choose to be a tzadik or rasha. Rashi answers this paradox by saying הכל בידי שמים חוץ מיראת שמים, which is somewhat ambiguous and implies that although Hashem knows the future about most events, He is unaware about the future of whether a person will be a tzadik or rasha. This is certainly impossible to accept. The maharshal explains that Rashi was never bothered by the paradox between Hashem knowing the future and the freedom of choice, rather rashi was bothered why the gemara assumes that if a zivug is done prior to yetziras h'vlad, it must not be based on merit. Maybe it is based on merit, yet Hashem knows the future. To that Rashi answers that Hashem may know what will be, but will not make a decree with a heavenly voice announcing the zivugin based on that knowledge, because a decree would remove the possibility of choice. Tosafos Harosh explains similarly, but seems to understand that even a decree would not negate free choice, but it would make people doubt the freedom of choice, therefore Hashem would not make a decree based on one's merit prior to them making those decisions.

Sotah 2a - Zivug of Tzaddik to Rasha

הדרן עלך מסכת נזיר - מזל טוב!! שנזכה להתחיל מסכתות אחרות ולסיימם

R' Shmuel bar Rav Yitzchok began his intro shiur to sotah by saying that matchmaking is done according to one's actions, meaning a tzadik with a tzadik and a rasha with a rasha. One of the meforshim in the back (Radal) comments that the purpose of this statement is to support the diyuk that was made immediately prior to this, that it is forbidden to give kinuy to one's wife. Meaning that since a spouse is always similar to the husband, if a husband suspects his wife of infidelity it can be attributed to his lack of fidelity. Therefore, rather than using drastic measures such as kinuy to change the situation (which will bring to fighting and embarrassment), it is preferable for him to change himself and turn himself into a tzaddik. By him transforming himself into a tzaddik, it will have an effect on her as well, since Hashem does not allow a tzaddik to dwell with a rasha. Perhaps we can extend this thought by saying that the process of the sotah water is really based on this premise that a rasha cannot be with a tzaddik, therefore the sotah water will ensure that she is as much of a tzaddik as he is, and if not she will be killed. This will explain the mishna 47a that when more men began commiting adultery the sotah waters stopped working. Meaning that the whole purpose of the sotah water is to prevent a woman who is a rasha from living with a tzaddik, but if he is a rasha the sotah water doesn't take effect (the ramban has a slightly different approach, that the sotah waters only work when klal yisroel on the whole are on a high spiritual level, and therefore act as a filter to remove the bad individuals, but when the entire nation drops they are no longer zocheh to this miracle).

Nazir 61a - Kibud Av for a Goy

The gemara discusses why goyim are excluded from nezirus and suggests that it is because in the parsha of nazir it insists on those who have paternity, which goyim don't have. At one point the gemara suggests that it is dependent on paternity in regard to honoring parents, which goyim don't have. I found this gemara somewhat troublesome in light of the gemara in kiddushin and avoda zara that tells the story of dama ben nesina, who is a goy in ashkelon used as the source for how far the mitzvah of kibud av v'eim goes. Had the gemara by us simply implied that goyim don't have an obligation to honor their parents, it would not strike me as a contradiction because even without an obligation they can fulfill a mitzvah. The problem is that the gemara doesn't just say that goyim are excluded from the mtizvah, but that they have no concept of paternity in regard to the mitzvah to honor one's parents. This implies that in regard to the concept of honoring a parent, goyim are created from immaculate conception and do not have parents. If this is true, how can we learn the mitzvah of kibud av from a goy?

R' Moshe (Dibros kiddushin heara 19) suggests that although goyim don't receive any reward for mitzvos between us and Hashem, because that requires a prerequisite of kedushas yisroel; they do receive reward for mitzvos bein adam l'chaveiro. Included in this would be tzedaka where the gemara implies a goy who performs this mitzvah indeed receives reward. Similarly, a goy will receive reward for the mitzvah of honoring his parents since it is a mitzvah bein adam l'chaveiro. Taking this approach one step further, it seems that the kibud av for a goy is not because he is a biological father who carries the paternity card, but rather because he is a person who invested in his son and deserves hakaras hatov. Therefore, out gemara is correct in that the fatherhood or paternity of a goy does not exist in regard to the mitzvah of kibud av, but we can still learn kibud av from dama ben nesina who certainly would receive reward for performing the mitzvah of hakaras hatov in an exemplary fashion.

Nazir 61b - Ba'al Yachel for a Goy

Tosafos (bottom of page) writes that there isn't any issur of ba'al yachel for goyim that binds them to keep their word. However, Tosafos in Avoda Zara 5b writes that if a goy would pledge a korban that is missing a limb and therefore invalid, they will be positively obligated to donate a proper animal as the korban. The mishne l'melech (Laws of kings 10:7) asks, where in the world does tosafos derive that goyim are included in the issur of b'al yachel, hence obligated to keep their word; the issur of b'al yachel and the mitzvah of keeping one's word was said specifically to jews, not goyim. He concludes by citing our Tosafos in Nazir who write explicitly that goyim are not metzuveh to keep their word. The Avnei Miluim (1:2) answers this question by saying that although they are not obligated to keep their word, when they make a pledge to the beis hamikdash there is a monetary obligation to fulfill their pledge, just as a formal acquisition would create a monetary obligation - amira l'gavoha k'msira l'hedyot. Therefore, they may not be obligated to keep their word, but they are obligated to pay their debts. The pledge of a korban to the beis hamikdash creates a monetary debt.

I remember that when i learned this tosafos in avoda zara (i had not seen the avnei miluim), i thought that this tosafos was a proof that even in the absence of a formal issur or mitzvah, a human being is obligated to keep their word. This concept seems necessary to explain how swearing prior to matan torah was binding, since there is no Torah committing them to keep their oath. Furthermore, this would explain the very essence of kabalas hatorah - that they were 'mushbah v'omed m'har sinai' - what binds them to keep their shavua of accepting the torah? the torah itself; what binds them to keep the torah? their shavua! v'chozer chalila.... But if we assume that keeping an oath is part of the essence of the koach hadibur that was giving to the human being, it would explain all this, and also explain Tosafos in Avoda Zara that goyim are also obligated to keep their word.

Nazir 58b - Hair Removal

The Gr"a (Y.d. 182:1) cites 3 approaches to the issur of men to remove hair on their bodies. 1. Tosafos based on our girsa, paskening like Rav, hold that the entire issur is only m'drabonon. The underarm and erva hair cannot be removed with a razor, but can be removed with a scissors, and the hair on the rest of the body can even be removed with a razor. 2. The Beha"g based on an alternate girsa (with the girsa of the word "ela") holds that there is no distinction between the underarm/ beis haerva and the rest of the body. There is an issur with a razor but it is mutar with scissors. 3. The Beha"g based on girsa without the word "ela" so that there are 2 distinctions being made, between underarm/erva and the rest of the body and between scissors and a razor. Therefore, the first distinction that the braisa that says you receive malkus is for the underarm and beis ha'erva, implying that it is an issur d'oraysa. The second distinction is that for the rest of the body, with a razor it is an issur d'rabonon, and with a scissors it is mutar. Based on this last approach, the issur of shaving underarms and beis haerva with a razor could be an issur d'oraysa even if done with a scissors (but even if it is not d'oraysa it is at least assur even when done with scissors).

The Shulchan Aruch paskens like the last approach that the beis ha'erva and underarm are assur even with scissors and the other parts of the body are assur only with a razor.

Regarding shaving one's beard, the shulchan aruch writes that since there is a big dispute about the "corners" that are assur, one should not pass a razor over any part of their face. The Rama adds to this "even under the neck". Although there is an opinion cited in the taz and Gr"a that one of the "corners" may extend to the neck (i.e. the adams apple), the beis yosef and gr"a reject this opinion. However, there is a source to assur the area directly under the chin because the skin of the chin will sometimes stretch below the chin (but this will not extend all the way to the neck itself). Therefore, the only rationale to forbid a razor on the neck is because it is tantamount to shaving with a razor on the rest of one's body which is the opinion of Rabbeinu Yona. The Gr"a rejects this approach as well because the only issur of shaving the rest of one's body is for beautification purposes where hair doesn't grow very densely yet he want to beautify himself by shaving it as a woman would do, but shaving the area of the neck where hair grows densely and it is not customary for woman to shave that area at all, there is no issur whatsoever. L'ma'aseh it seems that one can rely on the gr"a and be matir shaving on the adams apple and the rest of the neck below with a razor like the gr"a, but it is better to be machmir for the shita of rabbeinu yona paskened by the rama.

Nazir 57b - Makif and Nikaf

Long post today to make up for not posting every day.

Tosafos explains that we pasken like the opinion of Rav Huna that one is in violation for being makif a child, even though the child is not yet obligated in the prohibition. Although R' Ada understands that whenever the subject (nikaf) is not obligated, there is no prohibition on the makif either, R' Huna seems to reject this view. Tosafos explains that R' Huna rejects the drasha that exempts a makif whenever the nikaf is not obligated. I would like to suggest another explanation for the opinion of R' Huna. The categorization of a child not being a bar chiyuva (or not being a bar onshin), implies that a child is not considered in the realm of the mitzvah at all. Perhaps R' Huna understands that a child may not be obligated but is in the realm of the issur, therefore he is very different from a goy for example who is not at all shayach to this issur. Although R' Huna may in fact agree with the connection of R' Ada that whenever the nikaf is not a "bar chiyuva", the makif is exempt, he disagrees with the classification of the child not being a bar chiyuva in this respect.

Tosafos goes lishatasam. Based on their understanding that R' Huna rejects the hekesh of R' Ada making the makif dependent on the nikaf, asks why R' Huna would permit being makif a goy. Tosafos creates a new drasha to answer this, that "pe'as rosh'chem" in the pasuk is written only by jews, not by non-jews. Based on this approach Tosafos can't find a legitimate source to be matir a man being makif a woman, and therefore leaves it as a question whether it is in fact permitted for a man to be makif a woman. However, based on the approach that i suggested above that R' Huna agrees to the drasha, just that it doesn't apply to a child since the child is relevant to the issur albeit not "obligated". To be makif a goy or a woman would certainly be included in the hekesh, and R' Huna would agree that it is permitted.

In Y.d. 181:5 the shulchan aruch paskens like R' Huna that one cannot be makif a child. The Rama writes that one may be makif a goy or woman, but then cites those who are mesupak about that. The Gra quotes 4 opinions: 1. The Nemukei Yosef is mesupak whether one can even be makif a goy according to R' Huna. 2. Tosafos says a goy is pashut that it is mutar to be makif, and is mesupak about being makif a woman. 3. Tosafos in Shavuos seems to take for granted that only according to R' Ada would there be a heter to be makif a woman, but according to R' Huna it would be assur. 4. Rosh holds that one can be makif a goy and even a woman, even according to R' Huna, because the only issur is to be makif a kattan who is "אתי לכלל חיובא".

The Rosh seems to hold like the sevara that i suggested. R' Huna agrees that there is no issur on the makif whenever there is no issur on the nikaf. However, if the nikaf is a child there IS an issur on the nikaf even though he is not yet old enough to be muzhar. BUT if the nikaf is a goy or woman who are inherently excluded from the entire issur, there isn't any issur on the makif either. The Rama is matir based on the Rosh, and the Shach supports this opinion and comments that the bach and other ommit the opinion who is machmir about this.

Regarding a woman doing hakafa to a man, following R' Huna it should be mutar. The Shulchan Aruch paskens that it is mutar, but then says "yesh omrim" that it is assur. R' Akiva Eiger points out that even if we assume that there is no issur for a woman to be a makif, it would be assur for her to be makif a man since she is in violation of a d'rabonon of lifne iver (not d'oraysa since it is not trei avri d'nahara), but is then mesupak that since by her doing it, she will prevent him from doing it himself and violating a greater issur, she is actually saving him from an issur and therefore would even be mutar m'darabonon. He then suggests that even if it would be assur for a woman to be makif a gadol, it would be permitted for her to be makif a kattan as is apparent from the ma'aseh of R' Huna.

B'kitzur, if a father wishes to cut off his sons peios, he can't do it himself, nor can he tell a goy to do it because of amira l'nachri (pischei teshuva). The mother can do it herself, and can certainly tell a goy to do it . However, the proof that a mother can do it is from the story of R' Huna where Chova did it. Rashi explains that it was done as part of a refuah process. Therefore, if it is not being done for refuah, there isn't any proof from the gemara and it may in fact be assur m'drabonon. Also, if the hakafa to a child qualifies as hakafa, it should be assur even for a mother to do it because she is literally feeding him issur, just as she can't feed him any other issur. This is a question on how chova was able to do hakafa to her children, why do the meforshim (including R' akiva eiger) fail to mention this? I would like to suggest a big chiddush based on this question. The issur to be a nikaf although it doesn't require an action (except to be chayav malkus - shulchan aruch 181:4), it does require consent. The issur is not being in a state of hakafa where one's peios were cut off, rather the issur is to allow yourself to be shaved. Therefore, when one is makif a child, the child is merely a subject that hakafa was done on, but since the consent of a child doesn't qualify as consent, he is not considered a nikaf and shaving his head is not considered feeding him issur. In contrast, if one would bring a kohen child into a cemetery, it would qualify as feeding him issur as the poskim say since the issur is the effect of the tu'mah, not the decission to become tamei.

Nazir 54b - Mummies and Eretz Ha'amim

The Mishna L'melech (Avel 3:1) has a Teshuva where he discusses kohanim going into the mummy business. He begins by saying that although they may consist of very dry bones they are still metamei. However, his main tzad l'hakel is based on the opinion of the Yerai'im that we follow R' shimon bar yochai, that aside from goyim not being metmei b'ohel, they are also not metamei b'magah (Tosafos 54a clearly rejects this and says that even according to R' shimon they are metamei b'maga). Based on the combination of the Yerai'im, and the Ra'avad who says that any kohein who is already tamei (even after he separates from the meis) has not issur to become tamei again, the mishna l'melech creates a s'fek sfeika to be meikil, but eventually rejects it since it is clear from the many places including our Tosafos in the name of R' Chaim Cohen that a kohein cannot make himself tamei even if he is already tamei meis.

The issue that is related to our gemara is that the gemara in Avoda Zara 13a says that a kohein cannot enter into chutz la'aretz except for a mitzvah because of tu'mas eretz ha'amim. The Rambam in Hilchos Ohalos (2:3) seems to understand that the concern of eretz ha'amim is because of the fetuses of goyim that are buried there. This would clearly indicate that there is at least an issur of tu'mas magah and masah for kohanim to touch non-jewish corpses. However, the Mishna L'melech pushes off this proof based on Tosafos on our daf who says that the gezeira of eretz ha'amim is due to "the many jews that were killed in chutz l'aretz", not goyim.

BTW - Practically speaking, what happened ot the issur for a kohein to go from eretz yisroel to chutz l'aretz (other than for mitzvah purposes)? The Shulchan Aruch 369 rules that a kohein cannot go into eretz ha'amim, but the shach (3) writes that it only applies when eretz yisroel is muchzak b'tahara, but nowadays does not apply. This opinion is also quoted in the b'er hagola from the maharshal. The Shevus Yakov (brought in pischei teshuva) argues and claims that it applies even nowadays. R' Akiva Eiger justifies the minhag to be lenient about this either because parnasah is signifciant enough of a mitzvah (but this would not justify those who travel to chutz la'aretz for vacation) or because we are all tamei meisim. The second rationale seems to be either based on shitas ha'ravad that the issur of tu'mas meis in general only applies when the kohein is tahor, and although we are not meikil for tu'mah d'oraysa, we rely on the ra'avad for tu'mas ha'amim which is only d'robonon. But more likely he means to say that the entire gezeira of eretz ha'amim is in order to maintain the tahara of the kohein, and would not apply when the kohein is tamei meis.

Nazir 54b - Cherev K'chalal

The gemara on 53b learns from a pasuk the concept of "cherev k'chalal" which means that a metal kli that comes into contact with a meis becomes like the meis itself. We find 4 opinions regarding this din:
1. Rabbeinu Tam considers the cherev to be exactly like a meis. Therefore, a nazir who comes into contact with a cherev that was in an ohel ha'meis becomes a nazir tamei. Since kohanim are not allowed in contact with any tu'mah that causes a nazir to be migaleiach, a kohein is not allowed into an ohel where there is a metal object that came into contact with a meis. It would also follow that the cherev would be metamei a person through o'hel, and would be metamei the person for 7 days and he would require being sprinkled from para aduma on day 3 and 7 to become tahor.
2. Rabbeinu Chaim Kohein asks Rabbeinu Tam "what house would you build for me?", meaning that based on your premise a kohein should not be allowed into any house that has a metal nail in it since some metal in the house most likely came into contact with the meis. Therefore Rabbeinu Chaim Kohein holds that cherev k'chalal does not make a nazir be migaleiach, and therefore a kohein is not muzhar against it. However, Tosafos implies that even according to the is opinion, the cherev would still be metamei b'ohel and the person who became tamei through it would recquire sprinkling day 3 and 7.
3. Ba'al Hameor in chulin (mentioned in gilyon hashas) and Ramban in parshas chukas hold that the cherev does not make a person tamei through o'hel [which would answer the question of how a kohein can walk into a house with tamei metal, even if we assume like Rabbeinu Tam that a nazir is migaleiach for cherev k'chalal], only through direct contact or carrying. Furthermore, the person who became tamei from the cherev does not need any sprinkling from the parah aduma.
4. Rabbeinu Yitzchok Misimpunt (brought in Tosafos) claims that all keilim even non metal keilim are subject to cherev k'chalal, but Tosafos strongly rejects this approach.

Nazir 49a - Chazaka of being father

The gemara says that had the pasuk said by a kohen gadol that he cannot be metamei for his father, one can argue that it is because he is not definitely his father and purely based on chazaka, but a mother who is definite a kohen gadol can be metamei for (therefore it must also write "imo"). The Netziv asks, the logic is flawed. If the person that he believes is his father based on chazaka is in actuality not his father, then he is not a kohen. Therefore, if the assumption was that for a person who is definitely a parent, he can be metamei for, then he should be able to be metamei for his father 'mema nafshach' - if he is his father, he can be metamei [just like a mother], and if he is not his father then the son wouldn't be a kohen and can certainly be metamei for him?

The Netziv says a tremendous chiddush. Regarding the status of kehuna the chazaka is d'oraysa and definitely confirms the father to be the biological father, hence rendering the son a definite kohen. The logic of the gemara is based on an assumption that the pain of the loss is a contributing factor in allowing a kohen to be metamei for a relative. Therefore, one can argue that the pain is stronger for a mother who is definitely the biological mother rather than the father who is only based on chazaka. So, if the torah would only write that a kg cannot be metamei for his father, one would say that for a mother where there is more pain for the loss, he can still be metamei.

Obviously the Netziv is very difficult to accept that one feels more of a loss for a mother BECAUSE he is sure that she is his biological mother, as opposed to the father where there is some uncertainty despite the chazaka.

Perhaps the answer is based on the Ohr Hachaim (Emor 21:2). One can technically design a scenario where the son has a chezkas kehuna b'vadai, but is still only able to determine who his father is based on the chazaka. Meaning, his chezkas kehuna is stronger than the chazaka that the deceased is his father. Yakov and Reuven each have an independent chazaka of being a kohein [not based on their relationship to each other], and there is a chazaka that Yakov is the father of Reuven. Therefore, even if Yakov would not be the father of Reuven, Reuven would still be a kohein [perhaps based on witnesses who told him that they knew his father was a kohein, but did not identify Yakov as his father]. In this scenario it is plausible to suggest that if Reuven becomes a kohen gadol he would be able to be metamei for his mother but not for his father since the knowledge that Yakov is his father is based purely on chazaka. For this we need the pasuk of "imo" to teach that a kg cannot even be metamei for his mother.

Nazir 48b - Pushing off Meis Mitzvah for Pesach

The gemara learns out from the pasuk of "achoso" that even one who is going to do the mitzvah of pesach or milah that have kareis associated with them, push off the mitzvah 'sheyesh bo kareis' to fulfill the mitzvah of burying a meis mitzvah. The Tzlach in brachos 19b is very troubled by the fact that the Rambam fails to pasken this din. The Tzlach explains that our entire sugya that has "achoso" extra works only within the opinion that a gezeira shava on one side is sufficient to prevent refutation (not exactly like tosafos who tries to make this point a machlokes r' yishmael and r' akiva). But we follow the opinion of the Rabbonon in Nidah 22b who hold that we need a gezeira shava that is mufneh on 2 tzdadim to prevent being meishiv on it. Therefore, we end up without an extra pasuk of "v'lachoso" to teach that we override the aseh sheyesh bo kareis of pesach and milah for meis mitzvah, and the result is that the mitzvah of pesach and milah which have kareis do in fact take precedence over the mitzah to bury a meis mitzvah (like the gemara thought before the extra pasuk of "v'lachoso"). Based on this the Rambam leaves out the din of meis mitzvah overriding pesach and milah, because the Rambam holds that meis mitzvah does not override pesach and milah.

Nazir 47a - Nazir and Kohen Gadol, Reducing the Issur

Both a nazir and kohen gadol (kg) can be metameh for a meis mitzvah, but there is an argument in the mishna what should be done when they are walking together and chance upon a meis mitzvah. R' eliezer says that the kg should be metameh because he doesn't need a korban for his tu'mah, and the chachamim say the nazir should be metamei because he doesn't have kedushas o'lam (Tosafos seems to understand that even if he is a nazir o'lam, the concept of nezirus is limited to 30 days, so even when he extends it forever it isn't as powerful as kg which is inherently a kedushas olam. See also Rashash who seems to understand that it means that it is no'heg l'doros).

The Maharatz Chiyus asks in the name of the Sha'ar Hamelech: The Ran (yoma 4b b'dapei harif) explains that when a choleh needs to eat on shabbos it is preferable to shecht for him to violate the issur shabbos once, rather than to feed him neveila and violate the l'av of neveila on each kezayis that he needs to eat. Based on the Rambam (Nazir 5:21) that a nazir who deliberately makes himself tamei is in violation of 4 l'avin, it should be preferable to have the kg be metamei a more chamur issur once rather than the nazir violate 4 issurim. So why to the rabbonon feel that the kedushas olam of the kg requires the nazir to become tamei rather than the kg?

Perhaps the Ran's distinction only applies to a case where he will be doing multiple actions to violate the multiple issurim, such as eating one kezayis after another. But in a situation where he will be doing one action that violates a more chamur issur i.e. kg being metamei, or one action that violates many issurim in one shot i.e. a nazir being metamei, it is better for the nazir to be metamei.

But to me it seems that the real answer is: When we deal with violating issurim and the rule of thumb is "ha'kal ha'kal techila", meaning we reduce the level of issur, the Ran suggests that reducing the amount of issurim is more important than reducing the severity of the issur. Meaning, that one issur chamur is more "kal" than many lower level issurim. That concept only applies when we are basing our approach on "ha'kal ha'kal techila". However, when it comes to a nazir and kg who are in conflict which one should violate his kedusha to be metamei for a meis mitzvah, we don't look at the severity of issur, rather we look at their respective levels of kedusha. The individual with the higher level of kedusha can demand that the other be metamei, even if by doing so he will be in violation of more issurim. Therefore, the Chachamim hold that the kedushas olam of the kg gives him the upper hand to force the nazir to be metamei.

Nazir 43a - Meis Mitzvah

The Rosh and Tosafos point out from our gemara that one would only qualify as a "meis mitzvah" to allow a kohein or nazir to be metameh for them, if there is no one else around to do the job such as the case of the gemara where they are on the road and there is no one else to bury the person. Based on this hagdara of "meis mitzvah" Tosafos struggles with the gemara in yevamos 89b which says that a ketana married to a kohein where the marriage is only d'rabonon, he can be metameh for her when she dies. The gemara explains that since her blood relative don't inherit her, they will not want to bury her and she is like a meis mitzvah where we allow her husband to bury her. Tosafos asks, if the case is where there are others available to bury her so she is not technically a meis mitzvah, why should we allow her husband to be metameh? And if the case is where there is no one else around to bury her, it is an actual meis mitzvah and therefore his right to be metameh had nothing to do with being married to her (which is the implication of the braisa)? Both Tosafos here and Tosafos in Yevamos take the approach that she is not actually a meis mitzvah, but chazal have the power to uproot the issur of being metameh when there is a real reason to do so. Therefore although she is not technically a meis mitzvah, chazal treat her like a meis mitzvah and allow the husband to bury her.

Agav, Tosafos seems to imply that even if there are others around who refuse to bury the meis, since they technically are available to do so, the meis would not have a status of meis mitzvah (מדכתבו התוס' "אלא דאיכא אחרים דיכולים להתעסק וחשוב כמת מצוה, אלמא כהן ומת לפניו ויש שם ישראל ואינו חושש ליטפל חשיב מת מצוה, ואור"י דודאי מן הדין לאו מת מצוה התם וכו' - אלמא דכשיש שם ישראל ואינו חושש ליטפל לא חשיב כמת מצוה ודו"ק). I find this to be a big chiddush - why should the fact that there are others around remove the status of meis mitzvah if they are not actually willing to bury the meis?

Nazir 42a - Combing hair

The mishna says that according to R' shimon who is matir a davar sh'eino miskavein, a nazir is allowed to rub his hair but not allowed to comb it. Their seems to be different girsaos in the gemara as to why combing hair would be assur. Tosafos and mefaresh have the girsa of our gemara and explain that although it may not pull out hair, he intends to pull out loose hairs so it is a davar hamiskavein. But the Rosh and Rashi in shabbos 50b and 81b say that although it is not miskavein, it is a p'sik reisha that it will pull out hairs. It seems that according to the girsa that it is a davar hamiskavein, it is only a safeik whether it will pull out hair and therefore assur m'din safei d'oraysa (?), but according to the opinion that it is p'sik reisha it will be a vadai d'oraysa.

R' Akiva Eiger (gilyon hashas in shavuos 2b) asks a very interesting question. According to the opinion in shulchan aruch (tosafos) who says that we don't compare the peios harosh to peios hazakan, and therefore peios harosh are even assur to cut with a scissors, it should even be assur to pluck with a tweezers (because if not for a gezeiras hakasuv by peios hazakan requiring davka a ta'ar we also would have assured with tweezers). Based on this it should be assur to comb peios harosh out of concern that it will pull out hair (either because it is a p'sik reisha or because it is a davar hamiskavein)?