I'M SURE I'M MISSING SOMETHING, but what's the big deal of the cohenim doing what the Torah obliges them to do?
In Sefardi congregations, cohenim bless the people at every Shabat and hag.
Why the Ashkenazi don't follow the Torah re cohenim is beyond me. (I have heard several explanations.)
Numbers 6:23)
Yes, Leonard Nimoy, "Mr. Spock," was Jewish, albeit not a cohen.
I don't know about less observant or "non-traditional" synagogues, but in Sefardi and Mizrachi congregations the cohenim head for the Ark during the Amedah, a/k/a shmonah esray (18). In cohen-less congregations the reader recites the cohenic blessing.
According to Chabad, the reason the cohenic blessing is recited by cohenim only on festivals - vs., being read by whomever is leading the repetition of the Amedah - is because the recitation has to be done at a "joyous" mood, i.e., the festivals.
Bear in mind that since the Torah fails to specify exactly how the cohenim are to hold and wave their hands and there is no mention in Torah that listeners must cover their heads, different traditions will be observed, often within the same congregation.
halachipedia.com explains birkat hacohenim (cohenic blessing) for most - or at least many - Ashkenazi congregations. It notes that
The Ashkenazic minhag outside Israel is not to do Birkat Cohenim except at Mussaf of Yom Tov because Birkat Cohenim should be done when people are relaxed and not bothered by work. Throughout Jewish history, some have made a great effort to change this minhag (in order to fulfill this biblical Mitzvah) and were unsuccessful.
Some have the practice not do Birkat Cohenim when Yom Tov falls out on Shabbat, however, the poskim strongly disapprove of this and urge to discontinue this practice without causing conflict.
Rabbi Ben Hassan of the Sephardic Bikur Holim Congregation in Seattle, on his Ask Rabbi Hasssan notes that while he is Mizrachi, his studies of birkat cohenim explain why Ashkenazim omit the practice.
He starts off asking When we look at the formulation of the mitzvah of Birkat Cohenim it looks very clearly that it is a mitzva De'oraita - a positive mitzvah from the Torah for the Cohenim to bless the Jewish People every day. This is how it is codified by the Sefer HaHinuch. So how did the custom of not doing Birkat Cohenim daily start in the Diaspora? and then offers some answers.
In addition to the Ashkenazi reasoning, he discusses birkat hacohenim in Sefardic and Mizrachi congregations. He notes conflicting customs in Morocco; in Moroccan congregations in the U.S. birkat hacohenim is done every day.
* "Real cohen" In the U.S., and perhaps other Western countries as well, when Jews arrived at the immigration centers, they were asked for their family name.
Most Jews were known as "Peloni ben Peloni" until Napoleon controlled most of Europe and demanded that every citizen have a last (family) name. Jews, like other citizens, took names that reflected their trade, location, or interest.
Some of the names spoken were tongue-twisters for the immigration officials; some simply ignored the immigrant's answer and "assigned" what they considered a "Jewish" name - cohen, levi, aaron/aaronovitch, etc. Consequently, there are many "Cohens" in America who are not cohenim; not even levi'im. After several generations of being a "Big C" Cohen, their actual status might be forgotten.
