The Gemara on 78a says that if a Kohain Gadol has relations with a women who is both a gerusha and a alamana then he will be liable 4 sets of malkus, one lo yeikach and lo yechaleil for gerusha and another set for almana. Since the issur of lo yechaleil is making a women who was previous kosher into a chalala (77a) how can he be liable twice for the same person?
Aaron Kaplan, Ramat Beit Shemesh, Israel
This is another very good question but it seems to me that one can answer that he makes her simultaneously into a chalalah both because of the prohibition of gerusha and at the same time because of the prohibition of almana. Because it is simultaneous and you cannot say which pesul came first therefore you have to say that he made her chalalah for 2 reasons, so he gets 2 sets of malkus because for each pesul she was previously kosher until the 2 pesulim applied instantaneously.
However there seems to be another question here and that is - how at all can he be chayev for the gerusha since she was nischalel to kehuna before his beeyah? - see Tosfos Ri HaZoken and Pnei Yehoshua
Kol Tuv
Dovid Bloom
Follow-up reply:
Here is a better answer to your question. The point is that there is a prohibition for a divorcee and a separate prohibition for an almana. So when he had relations with this divorced almana he was mechalel her because of 2 separate lavin. Vayikra 21:7 states that a Cohen must not have relations with a gerusha and if he did so he is mechelal this aspect of her. In addition Vayikra 21:14 states that the Cohen Gadol must not have relations with an almana and verse 15 says that if he did so he is mechalel her. This is a different, additional chilul to the chilul of the gerusha aspect of her, because it is a different prohibition of the Torah, and this is the reason he receives 2 separate sets of Malkus.
KOL TUV
Dovid Bloom