I don't see why the definition of "natural born citizen" matters. He's a "citizen" as defined by the Fourteenth Amendment.
Article II, Section I of the Constitution requires the President to be "a natural born citizen, or a citizen of the United States".
Please correct me if I'm wrong.
that is not the end of the sentence. Please read further
No person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this Constitution, shall be eligible to the Office of President; neither shall any Person be eligible to that Office who shall not have attained to the Age of thirty-five Years, and been fourteen Years a Resident within the United States.
You cut it off.
"No Person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this Constitution, shall be eligible to the Office of President; neither shall any Person be eligible to that Office who shall not have attained to the Age of thirty five Years, and been fourteen Years a Resident within the United States. "
You have to consider the phrase "at the time of the adoption of this constitution". The founding fathers, were all citizens, but they weren't "Natural Born Citizens", so they grandfathered anybody who was a citizen at the time the constitution was adopted. After they died out, only the "Natural Born Citizen" would apply.
Please correct me if I'm wrong.
Note the emphasis.
Those commas mean something.