Grotius thinks that each person can renounce his state and leave the country. (n15: provided it is not to evade one's duty the moment the homeland needs us; this would be criminal and punishable; it would not be withdrawal, but desertion)
Gist of Idea
A person is free to renounce their state, as long as it is not a moment of crisis
Jean-Jacques Rousseau (The Social Contract (tr Cress) , III.18)
The obvious example is Britons going to America in 1939, or (more controversially) conscripts going to Canada to avoid fighting in Vietnam. I'm unclear whether the idea in the note is that of Grotius or of Rousseau). Is tax exile OK, then?
Rousseau,Jean-Jacques: 'The Basic Political Writings', ed/tr. Cress,Donald A. [Hackett 1987], p.203