NOTES for Deu 17:1-20
Judging by the laws the Book of Deuteronomy offers us, its author's social ideal is hierocracy. Here there is a clear concession, a refusal of the theocracy so dear to the hearts of the early prophets, even though Deuteronomy appeared in the milieu of the early prophets, in the early prophetic communities of the Northern Kingdom.
The early prophets were always closer to theocracy, the rule of a charismatic leader appointed by God, who led the people after him in God's name and for God's sake. Hierocracy, however, meant the authority of the priesthood, of the priestly community, the community of the Jerusalem Temple, which precisely at the time Deuteronomy was being written was gaining its first experience of participation in political life, not in the North, of course, but in the South, in the Kingdom of Judah.
The logic of the book's author was understandable: it was important to him to preserve the purity of the Torah, including as state law, and for this it was necessary to find people who, possessing power and authority, would at the same time be faithful to the Torah. The author of Deuteronomy found such people in the members of the temple community: the priesthood of Jerusalem possessed both power and spiritual authority in its country, and the priests naturally did not think of themselves apart from the Torah. If anyone could help the Torah be accepted and spread in all its fullness and purity as state law, it was precisely the priesthood of Jerusalem. The matter was complicated, to be sure, by the fact that relations between the two Hebrew states at the time the book was written were, to put it mildly, very tense. But the sacred writer was little concerned by them, since he himself was an obvious opponent of secular authority in the form in which it existed in the North.
Judah, however, was also a kingdom, and the author of the book understands this: pure Yahwism can be combined with royal authority, but on one condition, that the king strictly follows the Torah, turning aside from it neither to the right nor to the left. This requirement that earthly authority follow God's law can be considered quite universal; it is given for all times. Forms of government and social order may change, but the basic principle remains unchanged: in God's eyes, only authority whose representatives follow the Torah, at least not violating the commandments given by God, has the right to exist.