[Maurice Tift]

The founders were familiar with Vattel's The Law of Nations:

  § 212. Of the citizens and naturals.

   “The citizens are the members of the civil society; bound to this society by certain duties, and subject to its authority, they equally participate in its advantages. The natives, or natural-born citizens, are those born in the country, of parents who are citizens. As the society cannot exist and perpetuate itself otherwise than by the children of the citizens, those children naturally follow the condition of their fathers, and succeed to all their rights. The society is supposed to desire this, in consequence of what it owes to its own preservation; and it is presumed, as matter of course, that each citizen, on entering into society, reserves to his children the right of becoming members of it. The country of the fathers is therefore that of the children; and these become true citizens merely by their tacit consent. We shall soon see whether, on their coming to the years of discretion, they may renounce their right, and what they owe to the society in which they were born. I say, that, in order to be of the country, it is necessary that a person be born of a father who is a citizen; for, if he is born there of a foreigner, it will be only the place of his birth, and not his country.”

[djf]

And I will add that it was well known and read by the founders...

[DoodleDawg]

The founders were familiar with Vattel's The Law of Nations:

They were also familiar with William Blackstone:

"The first and most obvious division of the people is into aliens and natural-born subjects. Natural-born subjects are such as are born within the dominions of the crown of England, that is, within the ligeance, or as it is generally called, the allegiance of the king; and aliens, such as are born out of it. Allegiance is the tie, or ligamen, which binds the subject to the king, in return for that protection which the king affords the subject. The thing itself, or substantial part of it, is founded in reason and the nature of government; the name and the form are derived to us from our Gothic ancestors...The children of aliens, born here in England, are, generally speaking, natural-born subjects, and entitled to all the privileges of such. In which the constitution of France differs from ours; for there, by their jus albinatus, if a child be born of foreign parents, it is an alien."

[Beach333]

In further support of Vattel’s defininition is the fact that “Law of Nations” is capitalized in Article I Section 8, Clause 10:

“The Congress shall have Power To ...define and punish Piracies and Felonies committed on the high Seas, and Offences against the Law of Nations....”