Our Gemara on Amud Beis identifies an uncircumcised cohen as unfit for service in the Temple. Rashi says this refers to a person whose brothers died from circumcision, so it is unsafe for him to undergo it. Tosafos (Rabbenu Tam) here and in Yevamos (70a) disagrees. If it is unsafe for him to have a circumcision, he is not penalized. Rabbenu Tam says our Gemara’s case of an unfit uncircumcised cohen refers to one who is technically healthy enough, but too afraid. We may have sympathy for this poor fellow who was not circumcised as a youth and now is fearful (without anesthesia), but this is not sufficient duress to exempt him from the obligation.

How do we understand the conceptual difference between Rashi and Rabbenu Tam? According to Rashi, in the end, the uncircumcised person due to medical danger is like one who has a blemish: it may not be his fault, but it still renders him unfit. According to Rabbenu Tam, it is not even considered a deficiency if he has no practical ability to perform the circumcision. We might say that since this is a covenant, he is included in the covenant as any other Jew, since his refusal does not constitute a purposeful rejection. (Minchas Asher compares this to a woman who is also included in the covenant, though obviously cannot have a circumcision; see chrome://downloads/148_03_82.pdf.)

However, it may go deeper and relate to the discussion we had on Daf 16 about the degree to which recitation of the relevant texts and teachings of the sacrificial service counts as actual service. Similarly, regarding the teaching in Berachos (6a):

“Rav Ashi said: If a person intended to perform a mitzvah, but due to circumstances beyond his control, he did not perform it, the verse ascribes it as if he performed the mitzvah.”

Is it as if he really performed the mitzvah, or does he get credit as if he performed it, though it was not actually performed? By way of analogy, in Tefillah Zakkah we recite that the fasting on Yom Kippur, and its consumption of the fats and blood volume of our body, should be considered as if we offered the fat and blood of a sacrifice on the altar. Clearly, we are not suggesting that we are literally a sacrifice and subject to requirements such as being unblemished. Rather, we are asking that it count like a sacrifice. Yet, we also saw opinions (Magen Avraham, beginning of Siman 48 OC, and Rama OC 132:2) that the recitation of the various sacrificial services must be followed by adherence to actual performative laws, such as standing and not misreading the formula of the incenses.

Here too, perhaps Rabbenu Tam holds the cohen’s desire to circumcise counts as if he actually circumcised—not just a free pass, but full credit.