Existence is not a principle.
However legally speaking, nations do have a "right to exist," which brings us back to Israel/Palestine and Russia/Ukraine conflicts in the modern age.
Fun rabbit hole.
To quote Ernst Renan
> Let me sum up, Gentlemen. Man is a slave neither of his race nor his language, nor of his religion, nor of the
course of rivers nor of the direction taken by mountain chains. A large aggregate of men, healthy in mind
and warm of heart, creates the kind of moral conscience which we call a nation. So long as this moral
consciousness gives proof of its strength by the sacrifices which demand the abdication of the individual to
the advantage of the community, it is legitimate and has the right to exist. If doubts arise regarding its
frontiers, consult the populations in the areas under dispute. They undoubtedly have the right to a say in the
matter. This recommendation will bring a smile to the lips of the transcendants of politics, these infallible
beings who spend their lives deceiving themselves and who, from the height of their superior principles,
take pity upon our mundane concerns. `Consult the populations, for heaven's sake! How naive! A fine
example of those wretched French ideas which claim to replace diplomacy and war by childishly simple
methods.' Wait a while, Gentlemen; let the reign of the transcendants pass; bear the scorn of the
powerful with patience. It may be that, after many fruitless gropings, people will revert to our more
modest empirical solutions. The best way of being right in the future is, in certain periods, to know how to
resign oneself to being out of fashion.
https://en.wikipedia.org/wiki/Right_to_exist
