Originally Posted by BucEyedPea
Why is he not eligible?
He is a naturalized citizen, not a natural born citizen. A natural born citizen is someone who inherits their citizenship from their parents. Neither of his parents were citizens, so he could not inherit something from them that they did not have. However, he is a naturalized citizen because he was born on American soil.
This is direct quote from SCOTUS Ruling Minor vs Happersett. It has been requoted in other rulings and has never been redefined.
“The Constitution does not, in words, say who shall be natural-born citizens. Resort must be had elsewhere to ascertain that. At common-law, with the nomenclature of which the framers of the Constitution were familiar, it was never doubted that all children born in a country of parents who were its citizens became themselves, upon their birth, citizens also. These were natives, or natural-born citizens, as distinguished from aliens or foreigners.” Minor v. Happersett, 88 U.S. 162, 168.
It clearly states that the parents must be citizens for the child to be a "Natural-Born Citizen."