Question: I am a kohen who comes from America, where a kohen does not duchen (do Birkat Kohanim) if he is chazan. At the yeshiva I am at, even the chazan duchens. What should I do if I am asked to be chazan?

Answer: A mishna (Berachot 34a) states that a kohen serving as chazan should not duchen even if he is the only available kohen unless he is confident that he will be able to return to his place in chazarat hashatz without undue confusion. The Tur (Orach Chayim 128) cites the Maharam MiRuttenburg as saying that the ability to not get confused does not erase the problem totally but only allows duchening when the chazan is the only available kohen. The Shulchan Aruch (OC 128:20) and the Rama (ad loc.) follow this ruling. The logic is that the slight endangering of the quality of the public tefilla is warranted only if it is needed to ensure Birkat Kohanim will take place at all.

Some later poskim present ways of coming to a different policy. The Pri Chadash (ad loc.) reads the mishna differently. In practice, whether or not there are other kohanim makes no difference. The mishna starts by saying that even if there is no other kohen, a chazan who might have a concentration problem may not duchen. Once it introduces that this problem depends on the person, there is no reason for any capable kohen to forgo his mitzva of Birkat Kohanim.

The Magen Avraham (ad loc. 31) tries to explain a minhag he was aware of for a chazan to duchen even if there are others based on a societal change since the time of the gemara that many note. Nowadays, the chazan uses a siddur, in which case we can assume that he will be able to continue chazarat hashatz properly. While according to the Tur and Shulchan Aruch, this broad confidence in today’s chazanim is only enough to justify duchening when he is the only kohen, one can argue that it removes any effect of the problem and allows duchening in all cases. The Magen Avraham disagrees with this approach, because the poskim during hundreds of years of siddurim use did not write that the halacha had changed. However, he reasons that it is legitimate to follow it if this is the local minhag. The Mishna Berura (128:76 and Sha’ar Hatziyun 64) takes a similar approach to that of the Magen Avraham. This is also the practice of most Sephardi communities (see Ohr L’tzion II, 8:5; Yalkut Yosef, OC 128:62). However, the majority of Ashkenazim in Israel (especially, in Yerushalayim) follow the Pri Chadash and allow the chazan to duchen even if there are others who are doing so (see Dirshu 128:(84)). (Az Nidberu XIII:34 advocates a compromise. A kohen who is serving as chazan when there is only one other kohen should also do Birkat Kohanim, because many hold that Birkat Kohanim is a mitzva from the Torah only when there are two kohanim. However, he was unable to find a previous posek to explicitly make such a distinction.)

There are times when one whose minhag is to not duchen should do so. The Rama (ibid.) says that if someone calls him to duchen, which turns him into one who is obligated from the Torah to duchen, the obligation overpowers concerns of confusion. Poskim explain (see Yalkut Yosef ibid.) that generally when the kohanim are called, they do not intend for the chazan. One can argue that in shuls with the minhag that the chazan does duchen, the kohen chazan will thus be bound based on the Rama. However, in our shuls, the kohen is called too late, as a kohen who has not begun to approach the duchan before Modim may not do Birkat Kohanim (Shulchan Aruch ibid. 8). Nevertheless, just the fact that you are in a shul which has the minhag for the chazan to duchen is enough to follow the minhag. This is ostensibly so even for someone who has not joined the community in a manner that he should personally adopt all of their minhagim. Still, it would be best for someone like you to avoid being chazan at tefillot that have Birkat Kohanim, which is anyway a practice that many suggest for any kohen (see Birchot Horai 10:7).