[bvw]

Vattel wrote from the perspective of code law and not common law.

That distinction of terms may make sense to you but I think that no Founder would make any sense of it.

[wideawake]

They would have been aware of the difference between Continental legal systems based on Roman/Imperial models and the English common law. Their familiarity with Blackstone would aid in that, since his introduction is one of the more famous discussions of the distinction in legal history.