Right. Call it something else because a "sovereign individual" was anything but a "subject".
I am arguing that they adopted the usage of the word "Citizen" because they got this usage of the word from what Vattel had written in his "Law of Nations" instruction manual for creating a Republic.
I get that. But disagree with you. There is no reason to believe they borrowed this usage from Vattel because it's not apparent they borrowed anything else.
In U.S. v Wong Kim Ark (1898) the U.S. Supreme Court was asked to rule on: “Are Chinese children born in this country to share with the descendants of the patriots of the American Revolution the exalted qualification of being eligible to the Presidency of the nation, conferred by the Constitution in recognition of the importance and dignity of citizenship by birth?”
“To hold that Wong Kim Ark is a natural-born citizen within the ruling now quoted, is to ignore the fact that at his birth he became a subject of China by reason of the allegiance of his parents to the Chinese Emperor. That fact is not open to controversy, for the law of China demonstrates its existence. He was therefore born subject to a foreign power; and although born subject to the laws of the United States, in the sense of being entitled to and receiving protection while within the territorial limits of the nation—a right of all aliens—yet be was not born subject to the ‘political jurisdiction’ thereof, and for that reason is not a citizen. The judgment and order appealed from should be reversed, and the respondent remanded to the custody of the collector.”
The Supreme Court ruled 6-2 that: “[An alien parent’s] allegiance to the United States is direct and immediate, and, although but local and temporary, continuing only so long as he remains within our territory, is yet, in the words of Lord Coke in Calvin’s Case, ’strong enough to make a natural subject, for, if he hath issue here, that issue is a natural-born subject’
“Subject’ and ‘citizen’ are, in a degree, convertible terms as applied to natives; and though the term ‘citizen’ seems to be appropriate to republican freemen, yet we are, equally with the inhabitants of all other countries, ’subjects,’ for we are equally bound by allegiance and subjection to the government and law of the land.’
“…every child born in England of alien parents was a natural-born subject, unless the child of an ambassador or other diplomatic agent of a foreign state, or of an alien enemy in hostile occupation of the place where the child was born.
“The same rule was in force in all the English colonies upon this continent down to the time of the Declaration of Independence, and in the United States afterwards, and continued to prevail under the constitution as originally established.”–U.S. v Wong Kim Ark (1898)
When the two citizen parent theory was tested concerning the natural born citizenship of Barack Obama, the Indiana Court of Appeals ruled: “Based on the language of Article II, Section 1, Clause 4 and the guidance provided by Wong Kim Ark, we conclude that persons born within the United States are ‘natural born citizens’ for Article II, Section 1 purposes, regardless of the citizenship of their parents.”–Indiana Court of Appeals
As they gave up the word "subject" so too did they give up the character of a subject, including the concept of jus soli which is monarchical/feudal in it's nature.
I get that. But disagree with you. There is no reason to believe they borrowed this usage from Vattel because it's not apparent they borrowed anything else.
If it is not apparent to you, it is because you haven't been made aware of all the connections between Vattel and the creation of the United States. Vattel was the trigger that kicked the whole thing off. His book is what inspired James Otis to initiate the American revolution.
No one else at that time was writing about uniting states to form a Confederated Republic. His book advanced the idea and the colonists made it happen.
Beyond that, many ideas which were written into the Declaration, the Constitution and the Bill of Rights had their origin in Vattel's "Law of Nations."