Just wondering, how would you then differentiate between citizens of the US who were born there and those who were born elsewhere and later moved there without going into long involved explanations? [\green]

I suppose it's a atter of customary usage. As I understand it, "Native American" is, or at least can be, used for all the indigenous peoples of both Americas. For the truly pedantic , by "indigenous" I mean those who arrived on foot via the Bering Strait. Here in NZ the terms used most are "tangata whenua" - "people of the land", and "tangata tiriti", "people of the Treaty" - those who settled here after the signing of the Treaty of Waitangi.