In the US the body of law known as American Indian Law is, for the most part, based on a series of Supreme Court decisions. The three decisions known as the Marshall Trilogy form the basis for American Indian Law, and the Marshall Trilogy is rooted in the Doctrine of Discovery.
No part of American Indian Law is rooted in Native American traditions. While American Indian nations enjoy a degree of sovereignty enacting these laws, the laws have been imposed upon them based on the American legal system. What is known as American Indian Law is really not law made by American Indians but law made for American Indians in order to codify relations with the US government. So, when American Indians bring a case before the Supreme Court, basing arguments on American Indian Law, they are accepting, a priori, the plenary power of Congress to make their laws.
A bit of a Catch 22.