There's an interesting article on Belgian nationalism in the latest Salisbury Review.
The basic argument is that Belgium is the last of Europe's artificial nations. An 1831 treaty forced a Flemish majority to coexist with a Walloon minority, despite a lack of ethnic affinity.
What this means is that ethnicity is not the source of national unity it should be in Belgium and so the expression of it has long been suppressed. It is considered especially politically incorrect in Belgium for the Flemish to identify with their own ethnicity.
The problem, though, is to find something to replace ethnicity to keep an "artificial" nation like Belgium together. According to Paul Belien, who wrote the Salisbury Review article, it's not easy to find such a replacement.
In Belgium, money has been used to maintain the support of sections of the population, but without a natural source of group loyalty, corruption is widespread.
Some Belgian intellectuals have reached the stage of seeing a lack of national feeling in their country as a virtue. For instance, in 1998 a group of intellectuals published an Open Letter in which they wrote that they cherished the Belgian flag "because the latter does not represent anything".
Of course, in writing this they are not too far ahead of the liberal intellectuals in other Western countries. Liberal intellectuals generally don't like ethnicity as a basis of national identity. This is because an ethnic tradition is something we are born into, and this contradicts the liberal belief that our self-identity should be fashioned by our own individual will and reason.
Therefore, in the West we are no longer supposed to support the traditional ethnic identity on which our nations were built. We are supposed instead to support incoherent concepts like "unity in diversity".
But such concepts will only take us closer to the Belgian situation, in which the basis for shared loyalties and a willingness to sacrifice for the community has declined and a real sense of nationhood has given way to a post-nationalist "identity of non-identity" or a desire to attach to a superstate like the EU.