It all depends on whether you mean something mythical or practical by "national unity and political sovereignty." If you mean something mythical, like a perfect Rousseauvian coincidence of general and particular wills, it's not only unattainable but also undesirable. If you mean something practical, however, like a functioning national government that (relatively efficiently) taxes its citizens, provides social services, and is not debilitated by deadly civil wars or armed separatist insurgencies, it is achievable and has in fact been achieved in many countries -- some of them rather very poor in terms of national income -- that exist today. That's probably the minimum necessity for civilized existence under capitalism. Globalization of neoliberalism has certainly made a functioning national government difficult to maintain in the poorest areas of the world, though -- Congo, Haiti, Liberia, Somalia, etc. are good examples (some of which -- like Afghanistan -- have never really enjoyed one in its modern history).
Yoshie Furuhashi <http://montages.blogspot.com> <http://monthlyreview.org> <http://mrzine.org> * Mahmoud Ahmadinejad: <http://montages.blogspot.com/2005/07/mahmoud- ahmadinejads-face.html>; <http://montages.blogspot.com/2005/07/chvez- congratulates-ahmadinejad.html>; <http://montages.blogspot.com/ 2005/06/iranian-working-class-rejects.html>