From here (Rav Yosef answer to Rav Ada bar ahava) we see that Boaz' son from Rus could not have been appointed to a position of leadership, could his grandson?
Uri Deblinger, Bklyn, NY
You assume that the Gemara means that a Ger is not suitable for appointment as king if the Mother is not Jewish. This is indeed the opinion of Tosfos (Sotah 41b DH Oso) who says that for a king we need both the mother and the father to be Jewish. The Ran in Sanhedrin (37a DH Chad) says that even according to this opinion, the grandson would be suitable for a king.
However the Ramban (Yevamos 45a) Ran (Sanhedrin 37a) and Kesef Mishnah (Melachim 1:4) say that the Gemara means that even if the mother is Jewish a person is suitable, and even more so if a person's father is a Jew. In this case the son himself would be suitable.
Dov Freedman