Native Americans are going to be in a lot of trouble in the future. They have the highest outmarriage rate (how many of them marry non-Indians) in North America. It's something like 40%. If you demand such a high blood quantum to qualify as a real Native American, then it won't take long for entire generations to fall below that threshold and cease to exist as NAs, which will affect overall demographics. At the same time, if you lower it, then you're going to get a sea of people who don't look Native American claiming that they are, which will inevitably result in NA identity being diluted beyond repair.