My wife’s family had something similar. Great Great Grandfather on one side of her family was married and had 4 children, wife dies shortly after birth of last child, he then quickly marries Native American woman, he dies not too long after that, 2nd wife raises baby as her own child and everyone assumes it is her child, so family believes it has some Native American bloodline. This was in isolated Nebraska/Kansas border homestead country so not a lot of other people to know the real story. Was only recently thru various genealogical records were they able to figure out true story, no DNA test involved.
There was many marriages of an individual native American and a European colonist, particularly on “the frontier”, which also shifted over time. The majority of those were not marriages into the native American heritage and culture, but the other way around. When a “white” married into a tribe, to live with the spouse’s tribe, they were more inclined to become a part of the tribe and with children who continued in the tribe, which in those cases DID extended over time the children’s “native American” heritage and culture, with the “European” family record suggesting their ancestor was missing from the family, lost among the natives.
That persons children and their children would have no problem, unlike Ms Warren, identifying themselves as true native American, because of the long ago ancestors that, whether one white and one native, made their life and family with the tribe. Ms Warren NEVER had that heritage, no matter the tales told in her family, because that lone figure she claims her “heritage” from married out of the tribe & culture and into “white” culture. Her kind of “native American” link is repeated in millions of “white” Americans today. It is no basis for saying “I am native American” in the sense of “part of” the peoples who came here long before the Europeans.