Summary
In a case focused on a Native American man, John Elk, denied the right to vote after he left his reservation and began living among white people, the Supreme Court found that Native Americans were not citizens by birth under the Fourteenth Amendment and could therefore be denied the right to vote.
Source
“An Indian, born a member of one of the Indian tribes within the United States, which still exists and is recognized as a tribe by the government of the United States, who has voluntarily separated himself from his tribe, and taken up his residence among the white citizens of a state, but who has not been naturalized, or taxed, or recognized as a citizen either by the United States or by the state, is not a citizen of the United States within the meaning of the first section of the Fourteenth Article of Amendment of the Constitution.
A petition alleging that the plaintiff is an Indian, and was born within the United States, and has severed his tribal relation to the Indian tribes, and fully and completely surrendered himself to the jurisdiction of the United States, and still so continues subject to the jurisdiction of the United States, and is a bona fide resident of the Nebraska and City of Omaha, does not show that he is a citizen of the United States under the Fourteenth Article of Amendment of the Constitution.”