I thought I would move up the discussion of nations, nationalisms, and disintegrating empires up from the South Ossetia post into a new place. I've always been rather unconvinced with nationalist arguments against separatist groups, although I realize that the chaos caused by a national schism is almost always violent. Here are my rather unpolished musings on the subject as I tried to brainstorm examples of relevance. It seems to me that if the late nineteenth and early twentieth centuries were all about the rise of nations and the decline of empires, we are now dealing with the beginnings of some kind of post-nationalist moment.
Related to Spain, for example, I think that the Spanish government should allow those regions who claim to have their own language, culture, etc. split - they'll be tiny and economically weak, and I bet they'd come back to Spain eventually. Or else perhaps the way Europe is going is toward a complete reorganization of its borders so that all ethnicities and linguistic groups will relate via the European Union rather than to national governments.
Western Europe's old empires weren't all that different from its modern national boundaries (with obvious exceptions in the territory disputed in the two World Wars), but in Eastern Europe and in the Caucuses, the situation is obviously different with the historical Ottoman Empire and Russian Empire looming large.
Some places, like Lebanon, build incredibly delicate systems where sectarian identification divides up political rule - and then they just stop taking censuses for fear that new numbers might disrupt the existing order.
Others, like South Ossetia, emphasize their Russia-loving Ossetian majority over the Georgian minority. If so, why does Georgia want them so much?
Others look to the impossible question "who was here first?"
In China and Taiwan (or Chinese Taipei as Taiwan agreed to be called in the Olympics), it's a question of dueling political parties and how China and Taiwan both have connected past history to their national myths.
I think that as an American, it's hard to understand what's so difficult about living in a pluralistic society, and perhaps this is where my disconnect lies. So many Americans take diversity (even if it's just lip service) as our central identity. Yet the perennial controversies associated with immigration show that there are still fundamental knee-jerk ethnic ideas of who is and cannot be an American. I think there are like 90 history books written on this subject, so I'll just stop there.