“Considering the history of the constitutional provision, the clause’s apparent intent, the English common law expressly applicable in the American colonies and in all of the original states, the common use and meaning of the phrase “natural born” subject in England and the American colonies in the 1700s, and the subsequent action of the first Congress in enacting the Naturalization Act of 1790 (expressly defining the term “natural born citizen” to include those born abroad to U.S. citizens), it appears that the most logical inferences would indicate that the phrase “natural born Citizen” would mean a person who is entitled to U.S. citizenship “by birth” or “at birth.” Such interpretation, as evidenced by over a century of American case law, would include as natural born citizens those born in the United States and subject to its jurisdiction regardless of the citizenship status of one’s parents, or those born abroad of one or more parents who are U.S. citizens (as recognized by statute), as opposed to a person who is not a citizen by birth and is thus an “alien” required to go through the legal process of naturalization to become a U.S. citizen.
The weight of scholarly legal and historical opinion, as well as the consistent case law in the United States, also supports the notion that “natural born Citizen” means one who is a U.S. citizen “at birth” or “by birth.” The Constitution of the United States of America, Analysis and Interpretation, notes that “[w]hatever the term ‘natural born’ means, it no doubt does not include a person who is ‘naturalized,’” and, after discussing historical and legal precedents and arguments, concludes that “[t]here is reason to believe ... that the phrase includes persons who become citizens at birth by statute because of their status in being born abroad of American citizens.”—Qualifications For President and the “Natural Born Citizen” Requirement, Congressional Research Service
He’s paid by the word.
Natural born Citizen is NOT the same as natural born subject. The founders very specifically rejected the idea of natural born subjects, a term implying an irrevocable fealty to an elite sovereign. Natural born subject was a term of ownership and was used, among other things, to justify impressing as many able bodied, but otherwise unwilling "subjects" into his majesty's royal service as possible (typically as sailors). For this reason (gathering up as many able bodies as possible), qualification as a natural born subject was like a logical OR operation, thus being born of either of the blood of a subject or within the king's realm was qualification enough.
The founders thoroughly rejected this idea and considered every citizen as sovereign -- we were founded as a nation of sovereign Citizens, none higher than any other. Politicians, even up to and including the president, were intended to be the servants of We the People, the exact opposite of the system natural born subjects suffer under. The founders were familiar with the term and concept of "natural born subject" and they rejected it in its entirety.
Furthermore, it is ludicrous on its face to assume that the founders, who were articulately deliberate and elegantly succinct in their writings, inserted an entirely superfluous word into the phrase "natural born Citizen." If they had meant only "born citizen" that is exactly what they would have written, but they did not. As Chief Justice Roger B. Taney wrote in Holmes v. Jennison (1840):
"In expounding the Constitution of the United States, every word must have its due force, and appropriate meaning; for it is evident from the whole instrument, that no word was unnecessarily used, or needlessly added. The many discussions which have taken place upon the construction of the constitution, have proved the correctness of this proposition; and shown the high talent, the caution, and the foresight of the illustrious men who framed it. Every word appears to have been weighed with the utmost deliberation, and its force and effect to have been fully understood."The purpose of the presidential eligibility requirement was to ensure that those born with a naturally divided allegiance be excluded from ever becoming our commander-in-chief. For this reason, qualification as a natural born Citizen was like a logical AND operation, thus one must born one hundred percent exclusively American, both of blood (of two citizen parents) and of dirt (within our territorial jurisdiction).