Whenever the topic is American Indians, "Native American spirituality" is sure to come up. The stereotype is of a people deeply devoted to the spiritual traditions of their forefathers. When I hear this, I say to myself, "I bet not even 10% of Indians say their religion is Native American." Turns out I was right. Using GSS data, here is a graph of over 300 Americans who say they are non-white American Indians (AIs). (I exclude the Elizabeth Warren types.) I split the sample in half (1970-99 and 2000-16) to see if there are any trends.
First of all, most AIs are Christian. There is a trend away from Protestantism and toward Catholicism, Native American, or no religion. But even with the shift, fewer than 10% say their religion is Native--just like I guessed. When it comes to their religious profile, Indians are pretty similar to many other American groups.
I checked to see if liberalism predicts identifying one's religion as AI (thinking that adopting the old beliefs might be a sign of anti-Americanism) but the two are unrelated. The typical believer of this type is politically moderate.