People are naturally tribal in the sense of wanting or needing to be part of a close-knit group (or groups). It's a powerful instinct and any realistic political or social philosophy has to take account of it.
Ethnicity needn't come into it, of course. In an increasingly complex world, our group identities - more often than not - have nothing to do with 'race' or genetic relatedness.*
But our tribal instincts were originally based on such factors, and such factors still play a significant role.
My question is: how should one respond to this phenomenon?
Disapproval seems silly and futile.
On the other hand, encouraging a sense of racial identity and 'national self-determination' seems to me dangerous and irresponsible - though many (often well-meaning) groups, political leaders and governments encourage such thinking with great enthusiasm.
The only sensible approach seems to me to be to accept that ethnic loyalties are a fact of life, potentially dangerous, but not altogether negative.
The liberal left generally presents an incoherent - or at least inconsistent - view. They hold 'racism' to be a totally unacceptable attitude, and yet actively encourage a sense of racial identity in certain selected groups. In other words racial consciousness is good if your particular ethnic group has had a bad run in recent times, and bad if your people have done okay.
Ethnic or racial identification will be more important to some people than others, but it is arguably a universal human phenomenon and a constant of human nature.
Certainly not to be encouraged as a path to liberation and fulfilment (a crazy Romantic notion); or damned as an abomination if indulged in even in non-violent and moderate forms by white Europeans, for example.
There are problems with European racial consciousness, of course. People seeking to return to some imagined mono-ethnic paradise are deluded and maybe dangerous.
Associating oneself too strongly with the fortunes of a particular ethnic group (defined in racial terms) is, in my opinion, an unnecessary, misguided and often ultimately pathetic move. Those who identify with groups traditionally seen as having been exploited etc. run the risk of perpetuating a mentality of victimhood; just as those who identify with dominant groups often fool themselves (like football fans) into believing that they somehow share credit or glory for the achievements of others.
* Reflections on ethnic self-identification and nationalism always take place within (and are affected by) broader political and historical circumstances. My perspective here is decidedly Western, and most significant for recent debates have been memories of the colonial period and of the Nazis, and the current situation in various Western countries.
I would suggest, however, that the (at least in part ethnically-based) nationalism of a rapidly rising China will increasingly constitute the context - and perhaps the focus - of future discussions on these issues.