Well, you have United States vs Wong Kim Ark 169 U.S. 649 (1898) which said:
"[T]he real object of the Fourteenth Amendment of the Constitution, in qualifying the words, "All persons born in the United States" by the addition "and subject to the jurisdiction thereof," would appear to have been to exclude, by the fewest and fittest words (besides children of members of the Indian tribes, standing in a peculiar relation to the National Government, unknown to the common law), the two classes of cases -- children born of alien enemies in hostile occupation and children of diplomatic representatives of a foreign State -- both of which, as has already been shown, by the law of England and by our own law from the time of the first settlement of the English colonies in America, had been recognized exceptions to the fundamental rule of citizenship by birth within the country."
So, everyone gets to be citizens who are born in the US, except for those who are being imprisoned during times of war, ie, prison of war camps and those who are diplomatic kids.
The former are not "legally" in the US, they're POWs. They're not subject to US law, they cannot demand due process, they cannot get anything. They can't get up and walk around and do whatever they want. The second have diplomatic immunity, they're not under the jurisdiction of US law.
So, all babies born under US LAW are given birth citizenship, if they want it.