Yes, take things in context. So let’s understand that Vattel’s work was primarily concerned with established European lands such as Switzerland, nations with long-established populations and cultures living in close proximity to other nations with long-established populations and cultures. He wasn’t necessarily envisioning overseas colonies whose population was almost entirely fueled by immigration becoming nations of their own.
Yes, take things in context. So let’s understand that Vattel’s work was primarily concerned with established European lands such as Switzerland, nations with long-established populations and cultures living in close proximity to other nations with long-established populations and cultures. He wasn’t necessarily envisioning overseas colonies whose population was almost entirely fueled by immigration becoming nations of their own. Ok. Here's all the context you need:
CHAP. XIX.
OF OUR NATIVE COUNTRY, AND SEVERAL THINGS THAT RELATE TO IT.
§ 212. Citizens and natives.
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. Vattel's work was written smack in the middle of the colonization efforts by the European nations, so it's hard to imagine that the effect of the laws of nations, in relation to colonization, was lost on Vattel. Immigration was addressed by the our own Constitution, with that pesky "Natural Born Citizen" clause. Everyone is welcome, but only citizens born to citizens can be President, with an exception made for those who were only "regular" citizens at the time of the Adoption of this Constitution.