The gemara says on daf 18b that a melech is not allowed to serve on an ibur shana beis din because of a bias towars his army. My question is that the mishna says befeirush that a melech is not dan - which means he can't serve on a beis din. So why does the gemara have to come on to a reason of bias of supporting his army. Without that he is always ineligible to serve on a beis din?
Sendy G., Elizabeth, NJ
The Gemara later 19a writes that Malchei Beis David *can* judge.
However, the Meiri nevertheless asks your question, since those who are Me'aber Shanah must be *members of the Sanhedrin* and a king, even from Beis David, cannot be a member of the Sanhedrin (since noone is able to argue with him). How then can he be Me'aber the Shanah?
The MEIRI and TESHUVOS HA'RASHBA (6:190) answer that if a person was a Chacham Muflag, he could be from the Mezumanim for Ibur Shana even if he was not from Sanhedrin.
D. Zupnik