I have always* maintained that the legitimacy of any state extends only insofar as that state protects the rights of those it claims the authority to govern and those whom it claims to be under the jurisdiction of its laws.
No state has a "right to exist". No state *can* have any such right, because no state has any claim to *rights*, in the first place. Rights inhere in and belong only to the individual, solely by virtue of their existence.
States have powers, not rights.