In Article 2, section 1 of the US Constitution:
"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."
The requirement to be 'natural born' is clearly stated. However, the Founders went further in order to include those citizens who were not natural born but were citizens prior to the adoption of the Constitution.
It is clear that only those who were Americans prior to the adoption of the Constitution were being excepted from the natural born requirement.
Since Congress created the Constitution, Congress is the only body that can define the terms. However, it would take a suit like Trump is proposing to get the ball rolling on the issue. Once the SCOTUS gets involved, the Congress will have no choice but to act or let the court decide. If they leave it to the court, the definition can be changed by a different court in the future.
So what was a 'natural born' citizen at the time? Only someone whose father was an American citizen at the time of the candidate's birth. It was generally the rule that a child was born into his father's national allegiance so the child assumed the same citizenship as the father.
Congress has since allowed that a claim of citizenship can be made through the mother or even one of the grandparents but none of those were options at the time. It is what was in the Founder's minds at the time that governs the definition until the Constitution was/is again amended.
The reason there is confusion on the issue is because the US Congress left it to the states to define what natural born meant.
The 14th Amendment is cited as the authority for anyone born in the US being automatically a citizen of the US. That too, is contradicted by what was the clear intention of the time.
"Chairman of the House Judiciary Committee (39th Congress), James F. Wilson of Iowa, confirmed on March 1, 1866 that children under this class of aliens would not be citizens: We must depend on the general law relating to subjects and citizens recognized by all nations for a definition, and that must lead us to the conclusion that every person born in the United States is a natural-born citizen of such States, except that of children born on our soil to temporary sojourners or representatives of foreign Governments.
Framer of the Fourteenth Amendments first section, John Bingham, said Sec. 1992 of U.S. Revised Statutes meant every human being born within the jurisdiction of the United States of parents not owing allegiance to any foreign sovereignty is, in the language of your Constitution itself, a natural born citizen. If this statute merely reaffirmed the old common law rule of citizenship by birth then the condition of the parents would be entirely irrelevant."
http://www.federalistblog.us/2007/09/revisiting_subject_to_the_jurisdiction/What it all comes down to, is that a Presidential candidate must be a 'natural born' citizen, whatever that might mean, but includes certain requirements, to wit, must be born under the jurisdiction of the United States and both parents must be American citizens at the time of the candidate's birth and must meet the Constitutional requirements.
Being a citizen is one thing, being natural born is something entirely different.
Neither Obama, nor Rubio, nor Cruz qualify as natural born citizens. The Constitution, (which of course includes the amendments), is really quite clear on the subject.
In Article 2, section 1 of the US Constitution: br... (