Technically citizenship could be removed by deporting somebody if they are no longer "subject to the jurisdiction".

All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.

Present tense. Supremes presumably said that at birth they were subject so they have citizenship for life, but that's not what it actually says. All of us, anchor babies and real Americans, only have citizenship while subject to the jurisdiction.

Historically, in saner times, you only stop being "subject to the jurisdiction" when you renounced your country because jurisdiction meant your country, your allegiance; move to Russia, become Russian citizen, renounce American citizenship, you're no longer a subject.

But if the Supremes (haven't read it yet) say it's geographical then it can be taken away geographically. So we could have a law that says if an anchor baby is deported with their parents they're no longer citizens -- just have to make sure they never step foot on American soil again.