The Sanhedrin was a construct under Roman occupation, that came from disobedience and has nothing to do with God's King(David).  The King was always anointed by a prophet.  See Malachi 4:4,5--[5] Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the LORD:
[6] And he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse.These fathers and children are Israel, and the covenant made with God Almighty.Until the Return of the KingShalom
Betty