McCain’s Father was an American naval officer, as well as being an American citizen and had an American Mother. If you insist that he was therefore, becquse of his birth in Panama where his father was stationed, insist on saying his is not a natural-born American, you offer a reduction ad Absurdum to the other side. For the purpose of using the word was to debar a foreign prince from assuming this novel office. This was to avoid any suggestion of monarchy, and to rule out any non-American alternatives, such as Prince Henry of Prussia.
I believe that McCain's circumstance deserves an amendment. Many, at least twenty five, amendments have been tried and all failed to amend Article II Section 1, Cl 5. In fact in the first Congress there was a bill, signed by George Washington, making the children, born overseas, to US citizens into natural born citizens. But Washington signed the retraction of that law in 1795 and no bill has yet been created to change that. Some argue that the Supreme Court could change it, and wonder why they haven't acted. There is precedent, Minor v. Happersett, but I've been told that there is nothing to prevent a court from rejecting precedent and establishing a new interpretation. But thus far, they have not.
Washington's difficulty was probably one of separation of powers mixed with Article V governing amendments. Only the Supreme Court may interpret provisions of the Constitution, though I know of no case before 1790 in which that provision had been tested. Thus far, the court has used the common-law definition quoted by Chief Justice John Marshall, who cites Vattel’s Law of Nations as the most concise source.
Vattel did proffer his opinion that the foreign born children of military/government officials should be deemed natural born, but many of Vattel’s principles based upon The Enlightenment and natural law were not adopted by our framers, so there is no assumption that everything the Vattel said was assumed to be the intent of our framers.
Thinking about why there might hesitation about foreign born children of military citizens it isn't hard to see why our framers, very concerned with usurpation by someone with hidden allegiance for any other nation might have left out the Vattel extension to military families. Let us assume the military family had relatives in Britain, as almost everyone in the Colonies did. The mother may have died in childbirth and the child left to be raised by the grandparents in England. When the child is 18 he returns to live in the US and attends school. After 17 years in the US he is eligible to become President. Will he have the firmness of allegiance to the US to guide a fragile nation, which may face another war with England at any time? The Constitution was created to protect the sovereignty of individuals. There were many, some say almost half the population of The Colonies before 1776, who firmly believed in the need for a king.
I'm sure you can think of circumstances today where an Army Major, a Muslim and a psychiatrist, takes his Muslim wife on assignment to the Middle East. They have a child there and the child is left to be raised in Saudi Arabia for 15 or so years, returning to the US a “natural born citizen?” Would you trust the intentions of someone exposed to Islamic indoctrination for 15 years?
The law is what it is, even when political parties find it expedient to pretend Article II Section 1 has no relevance today. The current resident of the White House had his college education funded by the Saudi Family, and attended Mosques in Indonesia. We should have honored our Constitution, which, by the way, does not contain definitions by design, depending brilliantly upon the common-law and language familiar to its framers. That common law was repeated in about 40 supreme court cases, right up through 1939. There is no doubt.
That 1939 case made it clear that a young girl, Marie Elg, born in New York to naturalized citizen parents, taken to be raised in Scandinavia by her parents who repudiated their US citizenship, could not lose her natural born citizenship, and did return to live in the US after reaching majority, and could have run for the presidency. Natural born citizenship, the court opined, was granted by nature/God, and could not be denied by a congress of men.
The thought that went into defining citizenship was essential to the foundation of a nation based upon ideas, where leadership was not determined by blood lines. Thomas Paine observed that difference between England and the US, noting that in England the King must have been born to one parent who was an alien, and our President needed both to be citizens. Curiously, only natural born subjects of the British Commonwealth are eligible to be members of Parliament, where naturalized citizens can hold any office in the US Government besides the Presidency, with differing residency and age requirements for different jobs.