Sorry, but
this claim is utterly false. Elizabeth Warren's ancestry is actually pretty well documented, and she has zero Native American ancestry doing back to the 18th century. What was
found, ironically, is that she had a great, great, great grandfather who was in the Tennessee militia and who probably participated in rounding up Cherokees and sending them on their way on the Trail of Tears.
Of course, Elizabeth Warren's ancestry could be determined scientifically with a DNA test, but I'd bet a lot of money that she will never, ever submit to that. Regardless, the racial composition of her DNA is irrelevant.
At the time she was claiming to be a Native American for the purposes of advancing her academic career, she demonstrated zero interest in Native American culture or community. At Harvard, despite having been specifically identified as the only tenured woman "of color" in the Law School, she had zero contact with her purported community of color. She never participated in any functions or did any mentoring, or did any recruiting on behalf of the Native American community. Zero. It is one thing to claim some black ancestry (truthfully!) and benefit from affirmative action while doing nothing to identify specifically with the black community. There is precedent for that in the history of the "one drop rule." Not so with other ethnic identities however. And this goes doubly so for Native American identity since there have been many privileges granted to Native Americans throughout US history, and, consequently, there is a precedent for the rejection of numerous disingenuous claims based only on distant ancestry and not on cultural affiliation.