What important legal practice dates back to henry ii?

King Henry II established many basic principles like-

1- Assize of Clarendon that established the grand jury system for investigating crimes. Earlier it was ordeal for punishing the criminals but later it was disapproved by the Church so the jury system came to practice.

2- Assize of Northampton that established the jury of presentment to decide which cases should be tried.

3- Assize of Arms that ordered that all free men should keep arms and be prepared to defend the country.

d. migration of french settlers into english colonies

it was certainly a debatable decision, mainly because it was based primarily on political - and not on legal or social - views. since the congress at that time was led by members of the republican party, and the territory that the tribes wanted to turn into an exclusively indian state was predominantly democratic, the proposal (as expressed in the constitution) did not succeed, but the constitution itself proved to be of crucial importance in the creation of the state of oklahoma, and, most importantly, it guaranteed the involvement of representatives of the indian tribes in the government of the future joint state.  

as a member of congress, i would have voted to ratify the constitution, or at least to have it tabled. ignoring it was an interested and partial decision.