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Passports have absolutely nothing to do with the question.
The are strictly travel identification, not citizenship documents.
In this case the passport is indicative of a right to claim citizei. Born on US soil to two citizen parents, but with a right having absolutely nothing to do with US law or the Constitution to citizenship in another country. To make that person not a NBC would mean granting to other countries the right to determine eligibility to the US Presidency.
The are strictly travel identification, not citizenship documents.
In the USA citizenship is required to get an American passport, is it not?
A USA Passport is always accepted to prove citizenship, for places where such things are required, is it not?
This is the same in all nations I am aware of.