Parsha Mitzvot: Shofetim: Mitzvah 493 – Concept 591
“You shall surely set over yourself a king whom God, your Lord, shall choose.” (Deuteronomy 17:15) We are commanded to appoint a king from Israel. (Rambam, Hilchot Melachim – The Laws of Kings and Their Wars)
The clearest of all our early commentators is the Ran, who distinguishes between two types of leadership: 1) Authority which is based on Biblical law. The Sanhedrin was appointed to ensure the proper administration of that law. 2) The second kind of authority, which usually expresses itself in rulings which contradict Biblical law, is called Hora’at Sha’ah, decress promulgated in order to meet certain emergencies. Our Sages have said that the reason Jerusalem was destroyed was because the judges inisted on applying Biblical law (Bava Metzia 30) when they should have taken into consideration the circumstances prevailing at the time, and have made allowances before convicting certain people.
There is an allusion to this in, “You will remove from your midst guilt for the blood of the innocent.” (Deuteronomy 21:9) This verse could also be translated as, “You are destroying the blood of the innocent,” i.e. that on occasion innocent blood is spilled by inflicting punishment on the innocent due to prevailing pressures, such as in emergencies and in times of war.
Appointment of a king enables the nation to be administered expeditiously during emergencies; the king has the right to ignore certain Biblical laws. (Shnei Luchot Habrit – Torah Ohr – Shofetim)