General Discussion

Otherwise, from the text of the SAVE Act:

Documentary proof of United States citizenship.—As used in this Act, the term ‘documentary proof of United States citizenship’ means, with respect to an applicant for voter registration, any of the following:

“...
“(4) A valid government-issued photo identification card issued by a Federal, State or Tribal government showing that the applicant’s place of birth was in the United States.
“(5) A valid government-issued photo identification card issued by a Federal, State or Tribal government other than an identification described in paragraphs (1) through (4), but only if presented together with one or more of the following:
“(A) A certified birth certificate issued by a State, a unit of local government in a State, or a Tribal government which—
“(i) was issued by the State, unit of local government, or Tribal government in which the applicant was born;
“(ii) was filed with the office responsible for keeping vital records in the State;
“(iii) includes the full name, date of birth, and place of birth of the applicant;
“(iv) lists the full names of one or both of the parents of the applicant;
“(v) has the signature of an individual who is authorized to sign birth certificates on behalf of the State, unit of local government, or Tribal government in which the applicant was born;
“(vi) includes the date that the certificate was filed with the office responsible for keeping vital records in the State; and
“(vii) has the seal of the State, unit of local government, or Tribal government that issued the birth certificate.
“(B) An extract from a United States hospital Record of Birth created at the time of the applicant's birth which indicates that the applicant’s place of birth was in the United States.
“(C) A final adoption decree showing the applicant’s name and that the applicant’s place of birth was in the United States.
“(D) A Consular Report of Birth Abroad of a citizen of the United States or a certification of the applicant’s Report of Birth of a United States citizen issued by the Secretary of State.
“(E) A Naturalization Certificate or Certificate of Citizenship issued by the Secretary of Homeland Security or any other document or method of proof of United States citizenship issued by the Federal government pursuant to the Immigration and Nationality Act.
“(F) An American Indian Card issued by the Department of Homeland Security with the classification ‘KIC’.”.

I don't know. Maybe no Tribal ID actually meets the requirements and there's no way for Tribal governments to have a clue where a tribal member was born, whether 90 years or 90 days ago.

Then again, I've been told repeatedly that I'd need to present a passport or a birth certificate when I go to vote, a Real ID just wouldn't cut it because an expert in the topic hadn't actually looked at the text of the proposed bill, which specifically lists Real ID compliant identification first, ahead of passports.. So I'm skeptical.