I have got hopelessly lost in this thread, and do not know which example you are talking about. I think the question has got abt complicated for me anyway. All I can say is that I have seen nothing that suggests that the Laws of Nations had anything to say about internal warfare. (when you get down to it, it's all about protecting the property of the rulers from damage)
Touching on the other issue of the legitimacy of Napoleon's claim to the Spanish throne, Ferdinand had been taken on to French soil to make his abdication and his subjects were entitled to believe he had made it under duress and therefore that it was not binding.
regards,
Susan