McGrit v. OK isn't about what federal law means per se; it was about whether white majorities can nullify clear legal commitments to indigenous people by refusing to honor them. The latter is John Roberts's position. Fortunately, it lost: https://www.lawyersgunsmoneyblog.com/2020/07/neil-gorsuch-cancels-andrew-jackson
As Gorsuch says, there's not actually any real dispute about what the law says. The only real question is whether, as Oklahoma claims, white supremacist lawlessness magically becomes law at some point if you do it long enough
The majority is also devastating in pointing out the myriad of ad hoc justifications Oklahoma throws up to justify nullifying federal law, none individually serious and sometimes mutually exclusive:
"But if we recognize the legal rights of some native groups we might have to recognize the rights of other native groups and THEN where would we be?" --John Roberts
Roberts gets repeatedly checkmated, like Jackie Aprile Jr. playing an afternoon of chess against Garry Kasparov
"Yes, promises were made, but the price of keeping them has become too great, so now we should just cast
a blind eye. We reject that thinking."
a blind eye. We reject that thinking."