As I stated, when the states at independence kept the Common Law, the word subject was transformed to citizen. Vattel is foreign law, not the Common Law.
As Reagan said: "The trouble with our Liberal friends is not that they are ignorant... it's that they know so much which isn't so."
We tossed out Subject law. It was incompatible with a Republican form of Government. Laws declaring ownership over a child the minute it is born are contrary to natural law. They are monarchy law, and they suit the needs of a monarchy. They make servants of anyone born under their roof or on their land.
We kept the routine and usual parts of English common law. We tossed out everything that was incompatible with natural law, i.e. American law. We tossed out "Corruption of Blood." We tossed out taxes going to the Church of England. We tossed out Debtor's prison, and we tossed out subjectude and replaced it with citizenship.
The founders *DID NOT* transform "subject" into "citizen." They explicitly chose "citizen" to replace "subject", and they meant to sever all ties with monarchist law.