[Spirited]

Is there any provision in Torah for how the Sanhedrin is established, chosen, constituted?

[reelfoot]

Not too much in Torah, I believe: I think the beginning of the court system can be traced to Ex. chap. 18 where Jethro, Moses's father-in-law, urged Moses to delegate dispute resolution duties. I think for composition of the Sanhedrin, one would probably have to go to the Talmud.

[Red Sea Swimmer]

There are some rules outlined but the actual process of selecting and appointing the Sanhedrin is rather ambiguous. As was prophesied however, at the time of the revelation of Moshiach, the process and how it would unfold would become more clear as every new day passed.

Believe it or not we are at those times right now, and clarity is entering the equation in dazzling streaks of light.

As Aquinas noted, there is a certain gradation in all things. The universe is ordered, benevolent, expansive and stable. The process of re-instituting the Sanhedrin, the appointment of Moshiach and the building of the Third Temple/House for All Nations will also be along these lines.