Look up 31 CFR 515.300 and 31 CFR 515.299. By federal regulation any child born in the US is a citizen. Those same regulations can be changed so that any child born in the US to an illegal immigrant is not a citizen.
You can’t change it for anyone already born, that would be an ex-post-facto law. You can change it quite simply for future births.
showing 515.301 through 515.339
515.300 and 515.299 are not found on this Cornell site.
I used google to
site:www.ecfr.gov/ 515.301
found it then I searched for
site:www.ecfr.gov/ 515.300
site:www.ecfr.gov/ 515.299
Not found on both.
Are there more than one set of these Title 31 data? I have never searched CFR before.