Subject: Re: population collapse?
" no one and no group has an intrinsic right to enter another nation without that nation's prior permission, and no nation has an intrinsic obligation to grant permission"

Nations are made-up entities. At one time, physical boundaries were determined by geographic aspects (rivers, mountains etc.). But in modern times, nations are whatever they say they are and are willing to defend (sometimes via treaty and negotiation, sometimes by war).

National boundaries change all the time. Even our own aren't the same as in 1776 when we first declared our existence.
Look at a map from say 1945.