Who's a Native American? It's complicated

(CNN) – The recent controversy over Massachusetts congressional candidate Elizabeth Warren's Native American ancestry, where the campaign of her opponent for a senate seat called for her to release documents claiming her Cherokee ancestry, has caused some to ask: What makes someone "legitimately" Native American? And who gets to make that determination?

"Fundamentally, it's the tribe’s right to determine who its citizens are and are not. If we don't know (whether someone is American Indian), we can ask the tribe," said Julia Good Fox, professor of American Indian Studies at Haskell Indian Nations University.