Blood Quantum: A complicated system that determines tribal membership threatens the future of American Indians

Ryan Padraza Comes Last is a full-blooded Indian, Sioux and Cheyenne on his father's side and Assiniboine on his mother's. He will soon receive his Lakota name: "A Rope." (Comes Last raises rodeo horses and always has a rope in his right hand. He likes to call Ryan his "right-hand man.") But…