"Mustering the broad social consensus required to pass new legislation is a deliberately hard business under our Constitution. Faced with this daunting task, Congress sometimes might wish an inconvenient reservation would simply disappear," Gorsuch wrote. "But wishes don’t make for laws, and saving the political branches the embarrassment of disestablishing a reservation is not one of our constitutionally assigned prerogatives."
This repudiates a principle that America has widely used, which is simply ignoring inconvenient laws and treaties. They didn't just hand over a hunk of Oklahoma: they set a precedent for the reclamation of many other areas that were similarly taken over without due process. Anything not explicitly rewritten under law is now open to challenge for reclamation under previous treaty. That is a LOT of territory -- almost every reservation started out much bigger than its remains today.
I hope the tribal lawyers are scouring their archives for things to take back.
So, America's formerly perfect record of breaking every treaty seems to be broken. Wow.