It is clear that the mechanical transfer of false is a synonym "national interest" and "public interest" in the phrase "State borders" — "national border" can lead to unpredictable inter-ethnic conflicts.
Turn to etnogeograficeskoj the map of Europe. In 32 European countries 87 national minorities live. Many of them dispersed "dissipated". So, the Germans living outside of Germany in Belgium, Denmark, France, Poland, Russia, Romania, Italy, the Czech Republic, Serbia, and so on.
You can imagine what the consequences would be an attempt to separate peoples to exercise in practice the principle of the identity of national and State borders. Meanwhile, it happens in real life. For example, the dissolution of the former Yugoslavia and the proclamation of the independence and sovereignty of Slovenia, Croatia and other subjects of the old Federation clearly illustrates the role of the principle of the identity of State and national borders in an inter-ethnic conflict.
The principle of the identity of State and national boundaries