on national boundaries

In his book, The open sore of a continent, Wole Soyinka asks a question that I think will remain relevant as long as nation states exist.

when is a state?

Hopefully, by the time I finish with this book, we can answer the question when is a state?

At present, I am only interested in sharing a quote or rather a passage questioning the inviolability principle of national borders.

The inviolability principle of national boundaries is therefore a fictitious concept, born out of nothing more substantial than faith, and therefore every bit as questionable for those of the rational world. And even those whose existence is bound by faith, especially of the religious kind, are cautious to deny
specific boundaries to the provinces of heaven, hell, or purgatory. These are left severely to the imagination, free to be adjusted according to population proportions in the hereafter.

When Satan launched his takeover bid against the forces of God, it was, after all, an attempt to unify the celestial provinces, if Milton’s account in Paradise Lost is to be believed. This, however, proved one instance when the unity principle did not prove popular; the cultures, mores, and ethics of heaven and hell were simply incompatible, and a war of separate identities was won by the supposedly good side, while evil, on the side of unity, lost out ignominiously. Clearly the notion of unification for its own sake
and at any price has been faulted even in the metaphysical realms, so where, then, in this entire universe are we to find the philosophy of wholes and parts that endows one, rather than the other, with immutable authority?

The answer is Nowhere. Nowhere at all. It is we, the occupants of the whole or the part who must decide whether it serves our collective interest to stay together or pull apart. And we can only commence by a
recourse to history, the quality of life in the present and the tangible advantages, as well as the projection that we can make into the future, stemming from today’s realities in all fields of our human activity.

What do you think of this position? Does it make sense and what, if taken to its logical conclusion, would it lead to in regards to national boundaries.