I'm even sympathetic to it. I agree that preserving the cultural institutions of (in this case) the Cherokee people is an extremely worthwhile endeavor. But, "being a member of the Cherokee tribe" doesn't mean what it once did. "Being a Cherokee" today means that one of your ancestors wrote his or her name down on a list over 100 years ago. That's *if* they were eligible to sign at the time and agreed to. This excluded a great many Cherokee.
The [Dawes] Act allowed for widespread fraud by government officials and legally stripped Native Americans of much of their land by allowing land not allotted to be opened to settlers. The Dawes Roll was the official roll of the Dawes Act and was open from 1896-1907. In order to receive a parcel of land Cherokees had to sign the rolls. In order to sign the rolls a Cherokee had to have a permanent residence in the Cherokee Nation and have appeared on previous rolls. Those who signed the Dawes Roll provided their names and blood quantum and in return were granted a piece of land in the location they desired. In addition to the "Cherokee by Blood" portion of the Dawes Rolls, there were separate rolls for Cherokee Freedman and Intermarried whites living in the Cherokee Nation. ... There were a number of Cherokees who did not sign the Dawes Roll. Some Cherokee who lived in the Cherokee Nation and were eligible to sign the roll and receive land refused to do so. After years of broken treaties and bad policies implemented by the US government, many Cherokees were weary of signing the Dawes Roll and "registering" as Cherokee. Other Cherokees of the day were not living within the Cherokee Nation and were therefore ineligible to enroll. Cherokees who had settled in Texas, Arkansas, Kansas, and Missouri were considered US citizens and were ineligible to sign the Dawes Rolls. Anyone descended from these Cherokee will be unable to enroll in the Cherokee Nation, even if they are able to prove their Cherokee heritage.

http://www.allthings..._gene_121100.html
So, from my POV, it's not clear to me that the law the biological father depends upon is any more or any less applicable to him than to anyone who has a Cherokee ancestor (and we are legion, let me tell you). I guess what I have a little difficulty here with the dissenting opinion is the presumption that "membership in the tribe" is an indication that an individual is any more or any less likely to be an agent of the preservation of the culture. In light of the fact that a two-year-old was ripped from the only parents she'd ever known and given to a father who was callous enough to dispense with "his responsibility" via a text message, I can't say that I disagree with the majority in this case at least as concerns the well-being of this one little girl.