This is more an observation than a strict analysis, but very interesting, nonetheless.
Nationalism seemed to die in much of Eastern Europe towards the end of the 20th century as Europe reeled from centuries of war. It seemed unlikely to many that it would return soon. But, of course, geopolitics marches on. Nationalism is back in Europe, and back in a big way. A few examples of interest:
Germany: The Germans have pushed for a leadership role in Europe with the onset of the Greek crisis. Rather than an isolationist nationalism, Germany seeks to exert its will over Southern Europe, lest the debt crisis bleed it dry. The Germans are likely to come out of the debt crisis with a considerable amount of power in Europe--which is the only way they can make the EU work for them. Otherwise, they will consider leaving--the EU will only be a deal the Germans will tolerate so long as it is not one that tears them down.
Hungary, Czech Republic, Slovakia, Bulgaria, Austria: Right-wing (sometimes seriously so) nationalist parties have made huge gains over the past two years. Much of this is in response to the Russian resurgence (where the options are to fight or join). But this resurgence makes for a potentially rivalrous situation in Eastern Europe. Territorial squabbles may arise and prevent Eastern European unity against Russia.
Denmark, Switzerland, France, and Holland: Right-wing and largely anti-Islamic parties have made great gains in Denmark and Holland in their last elections, signaling a reaction against growing Muslim influence in much of Europe due to massive immigration. France has banned burqas, and Switzerland has banned minarets. Anti-Islamism has become a relative European hallmark. Europe is set for a strong showdown with the Islamic world, but one very different from that of the US.
Belgium: Perhaps the most interesting of the nationalist movements, the Flemish movement has made big gains in Belgium, capturing 20% of seats (far more than any other party). Unlike previous separatist movements, this independence party is largely mainstream (rather than right-wing), and hopes to see a gradual dissolution of Belgium into Flanders (a Dutch region) and Wallonia (a French region). Belgium is probably closer to its end than ever before.
The return of Nationalism to Europe will make it a geopolitically interesting continent once again (after two decades of relative calmness, saving the Balkans).