מקרב אחיך תשים עליך מלך לא תוכל לתת עליך איש נכרי אשר לא אחיך הוא
The Sefer HaChinuch writes that we may not establish one who is not m’zera Yisrael (having the blood DNA of the seed of Yisrael) over us as a king. This applies even if the person is a ger tzedek, righteous convert. The shoresh ha’mitzvah, root of the mitzvah, is due to the fact that zera Yisrael are rachmanim, merciful. It is critical that he show mercy to all Jews and not impose upon them a heavy yoke which they are unable to bear. He should love truth, justice and righteousness, which are qualities that descendants of Avraham Avinu possess. The…