This concept has been well-defined and well-precedented throughout history. First precedent and proof of concept: Ancient Greece. To be a citizen OR a ruler in ancient Greece, you had to be born to two citizen parents on the soil of your city-state. Everyone else was an alien, who could enjoy the protections of the nation but couldn't vote or participate in the political process in any way.READ MORE
It is well-documented in the writings of Solon and Isocrates, chief legal writers of ancient Greece, but also in Plato and others’ writings. It was also the first example in world history of self-government of a republic by citizens under the Rule of Law based on Natural Law.
America is only the second such example in the world. The second definition of the natural born concept in history is found only in Vattel, who gave it the name: Natural Born Citizen, as quoted here, which inspired our framers sufficiently enough to include it in Article II as our presidential eligibility requirement. From our nation’s founding period until today there have been some 1063 references to ‘natural born citizen’ in legal, historical and court documents and written opinions. In every case where the term was defined in those writings, it was defined only one way: as being born to two citizen parents on the soil of the nation.