Tribes were sovereign, signed treaties that enshrined sovereignty—within limits,to be sure—and continue to exercise that sovereignty. Nothing is being handed over, it’s always been there.

Interestingly the idea that tribal membership is based on ancestry originated with Europeans and (white) Americans, more than native tribes. Historically (generalizing wildly), tribal membership is about citizenship in a community much more than it is about who ones’ grandparents were. Blood quotient was a US legal concept that reflected the American fondness for racial categories. A Navajo friend has Scottish and Arab ancestors who’d married into the tribe, just to give an example. Or check out _The Unredeemed Captive_, for a practice that would make no sense if tribal membership were racial.

Communities often want to continue as communities, in a way that’s only possible with self-determination. That can land as either a left- or a right-flavored interest, depending on who’s asking and the overall context. But it’s too big a part of human nature to brush aside.