“ In addition, a high priest who commits a capital sin must be tried by a court of 71.
War of free choice - Some wars are required, such as the biblical order to destroy Amalek, but wars that are not required must be declared by a Sanhedrin, not by a king or priest or smaller court.
City of idolatry - The Torah explains that a city of idolatry must be burned completely to the ground and nothing in it (human, animal, or property) must survive. This mishnah restricts the use of such a verdict, disallowing any city on the border or any group of three cities to be proclaimed as cities of idolatry. ”