Not a lawyer nor a Constitutional expert, but I’ve seen lots of opinions on the meaning of ‘natural-born citizen, including some that said my dad and uncles weren’t natural-born citizens because my grandfather had not yet gotten his American citizenship at the time of their births, regardless of the fact that grandma was an American citizen and that they were all born in the U.S.
To answer the question we need to try figure out what the authors of the Constitution meant when they wrote the words. The phrase reads: “No Person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this Constitution, shall be eligible to the Office of President”. This means that they were OK with someone becoming President no matter where they were born as long as they were citizens when the Constitution was ratified.
Naturally, all of the Founders were citizens of another nation, Great Britain, at their births, but had Lafayette, Von Steuben, or Pulaski become citizens before the Constitution had been ratified, they would have been eligible to be President.
This implies to me, that they weren’t all that worried about parents’ citizenship status but rather the individual in question. But I’ll admit I could be wrong.
The Supreme Court considered what the original meaning of NBC was in Wong Kim Ark. Long read but important to anyone who wants to know what the ORIGINAL INTENT was:
https://www.law.cornell.edu/supremecourt/text/169/649
“The fundamental principle of the common law with regard to English nationality was birth within the allegiance—also called ‘ligealty,’ ‘obedience,’ ‘faith,’ or ‘power’—of the king. The principle embraced all persons born within the king’s allegiance, and subject to his protection. Such allegiance and protection were mutual,—as expressed in the maxim, ‘Protectio trahit subjectionem, et subjectio protectionem,’—and were not restricted to natural-born subjects and naturalized subjects, or to those who had taken an oath of allegiance; but were predicable of aliens in amity, so long as they were within the kingdom. Children, born in England, of such aliens, were therefore natural-born subjects. But the children, born within the realm, of foreign ambassadors, or the children of alien enemies, born during and within their hostile occupation of part of the king’s dominions, were not natural-born subjects, because not born within the allegiance, the obedience, or the power, or, as would be said at this day, within the jurisdiction, of the king....
It thus clearly appears that by the law of England for the last three centuries, beginning before the settlement of this country, and continuing to the present day, aliens, while residing in the dominions possessed by the crown of England, were within the allegiance, the obedience, the faith or loyalty, the protection, the power, and the jurisdiction of the English sovereign; and therefore every child born in England of alien parents was a natural-born subject, unless the child of an ambassador or other diplomatic agent of a foreign state, or of an alien enemy in hostile occupation of the place where the child was born.
The same rule was in force in all the English colonies upon this continent down to the time of the Declaration of Independence, and in the United States afterwards, and continued to prevail under the constitution as originally established...”
The child of an illegal alien would NOT be a NBC because they were not under the authority of the government at the time - just as an ambassador or foreign soldier is not. All the rest? NBC.
The key to what they meant is in the word "citizen." The correct and proper term used to refer to people who owed allegiance to a nation was "subject."
The use of "subject" was universal at that time, and only one nation in the entire world used the word "citizen." That nation was Switzerland, which was a Republic.
This is clear evidence that we adopted the Vattel definition because if they had wanted to keep the English law connection, they would have continued to use the word "subject."
Rejecting "subject" is rejecting Jus Soli.