hree Theories: Today, there are three conflicting theories regarding the meaning of “natural born citizen” in the U.S. Constitution:
The citizenship-at-birth theory defines “natural born citizen” as anyone who acquires U.S. citizenship at the time of her or his birth [14]. In the Naturalization Act of 1790, the phrase “natural born citizen” is used only in reference to children who are U.S. citizens at birth; persons who become U.S. citizens after they are born are considered merely as “citizens” [15].
The birthplace-only theory asserts that every child born on U.S. soil (except the child of a foreign diplomat or enemy invader) is automatically a U.S. natural born citizen, regardless of the nationality or immigration status of the child’s parents. The phrase “natural born”, as used in the Constitution, appears to originate from 18th century English law. Nearly all children born on English soil were, at birth, “natural-born” subjects of the king, regardless of whether their parents were English or alien.
The exclusive-citizenship theory (also called the two-parent theory) defines “natural born citizen” as one who, at birth, is a citizen of the United States exclusively and is not a citizen or subject of any foreign country. The only way to guarantee exclusive U.S. citizenship at birth is to be born on U.S. soil, of parents who are both citizens of the United States exclusively. Birth in a foreign country, or birth to a foreign-citizen parent, leaves open the possibility of foreign nationality at birth [16].
The citizenship-at-birth theory is mentioned here only for sake of completeness.
The most wrong of the three is the second: “birthplace-only theory” because so many facts of history contradict it.
It is essentially true that the reason for including this provision in the Constitution was certainly to protect the nation from foreign influence. That is, however, not the same as original intent. Original intent has to do with the explicit meaning of the words as the founders intended. That is, their purpose was to protect the nation from foreign influence, but the means by which they did was was a specific requirement.
While the Constitution does not give us the definition of natural born citizen or determine with any certainty which of your three theories would apply, other facts of history make it clear.