Admittedly, this is about whether someone's an "Indian," which is a particular type of race. And a fact that clearly matters for purposes of the Major Crimes Act, which provides federal jurisdiction for certain crimes committed by Indians in Indian country. So I understand why it matters -- and why we have to examine -- whether Shane Maggi (as well as Gordon Mann) are "Indians."
Still, my mind couldn't help but draw the analogy between this opinion and those earlier cases about who's "really" black. One drop of blood? "Recognized" by the state as a mulatto? Those cases leave a strong taste in one's mind. And it's not a good one. So to see a modern case that makes an (even loosely) analogous inquiry is a little disturbing.
Again, we're talking about Indians here, and at least a little about sovereignty, so perhaps the more accurate analogy might be to determinations about who's really "French" or "German". But however accurate, that's not where my mind first went.
None of which is to insult the opinion. The inquiry is, again, doctrinally required. But even that says something. Or at least reminds us.