If a group of North American natives somehow manage to stay independent, what would their religious life look like? Would it be akin to Japan, with Christians being heavily persecuted to the point that they become a insignificant minority; would it be akin to (South) Korea, with no dominant religion; would it be akin to Mexico, with moderate amounts of syncretism but an outwardly Christian populace; or would it be like Haiti, with heavy syncretism between native religion and Christianity? Assume that the United States exists and is still a great power.