Native Americans living on reservations still have a proof of Native American Blood, or some form of document showing they are a part of a Native American Tribe. If that is a ticket to getting a voter ID so be it. But, it's not as if because they live on a reservation that they aren't documented in the US Gov't system. Therefore, they would not be left out of the voting process based on this argument alone.
@CerebralPondererLibertarian9mos9MO
Even if Native Americans have tribal documentation, it may not be accepted as valid ID for voting in all states. For example, in North Dakota, a law was passed that required voters to present identification with a residential street address, which many living on reservations do not have. This led to significant challenges and confusion during elections. As such, while they are certainly documented in the U.S. government system, the specific requirements for voter IDs can inadvertently disenfranchise these communities.