So the Indians don’t live up to treaties either.
They cannot change a treaty by tribal law.
ART. 6, Clause 2: “This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding.”
I don’t know how the current tribe got around that one, but they did.