This is a subject which has been brewing for decades.   I'll use the term "Indian" as that's the term most folks use. There are many issues which weave in & out that it is almost impossible to explain without asking you to read the complete history and lineage of the entireity of all the Indian Nations of the USA, but this has become a symbol of the "Indian" wondering what else can they possibly take from us? But, the basis of this goes back to the greed of the rich non Indian.
   After peoples of various tribes had been given allotments of land--land which was supposed to be theirs "forever," it was discovered that something was under the land. Therefore, a mad scramble ensued, especially in the region of Oklahoma (where I come from) to become "Indian" in order to get land, & hopefully the oil underneath, & everything else which could be grabbed. Therefore, many people went downtown, or to various "Indian" agencies, claimed they were of whichever tribe (no documentation needed), & got a little card which made them become "Indian"--what came to be referred to as an "instant indian." Fastforward several decades & non-indian people have discovered that a few bands of some Cherokee tribes have a little bit of benefit(& I do mean little! Very little US government funding still trickles down these days as most programs for needy folks were axed by congress in the past several terms), such as medical or other programs. They say, "hey, was'nt great grandpappy a little bit Cherokee? Well, let's go to & research the Dawes rolls & find out if we can get in on some of the stuff they're giving away."
My grandad told me that his Aunt & Uncle did not want to admit that they were Choctaw, as back then the Choctaw people were considered to be especially dirty "Indians." Therefore, the Aunt & Uncle became instantly Chickasaw roll members on the Dawes Rolls.
This is to some an oversimplification, as questions such as those of the Freedmen come up, yet at some point a decision needed to be made, therefore-right or wrong-the vote.