The question is what constitutes “Natural Born”?
The most logical reading of that term is someone who is a citizen by virtue of their birth, as opposed to a naturalized citizen. By US law, a person is a citizen at birth if, A) they are born on US soil (including US territories, military bases or embassies); or B) they are born to at least one parent who is a US citizen. There are people who will argue that NBC refers ONLY to those born on US soil to 2 US citizen parents, but no court has ever upheld that definition, so that is their own opinion, not fact.