Even by the 90s, when I knew Crow kids, "second class" doesn't even begin to describe the discrimination they faced. "Prairie nigger" is a term that got thrown around--and wasn't objected to by a sitting US senator.
As far as I can tell, things haven't improved. My nephews' dad is native by race, but was raised by adoptive white parents. Looking "half Indian" nets all kind of assumptions--some innocuous but cringeworthy, others pretty ugly.
I don't know what the right answer is, but the US needs to figure out how to be less shitty to its indigenous peoples. New Zealand is far from perfect, but from my observations there, engagement with Māori is miles better than anything here.