I think the question becomes, at what point do we use cross-cutting concerns to identify our tribes? Class is the obvious example...when do middle-class people

I think the question becomes, at what point do we use cross-cutting concerns to identify our tribes? Class is the obvious example...when do middle-class people of different national, ethnic or political backgrounds band together to realize that their interests are far more aligned than they are with people who share those other traits but have a different financial reality, either because they're much poorer or much wealthier? I'd argue that for the upper class, that distinction has already been made. Rich people already view themselves as trans-national and move their money, resources and influence to wherever they feel it best suits them. They hold meetings in ritzy Swiss mountain towns to discuss common concerns and have residences all over the world, regardless of which country or countries issued them passports. The reason the discussion about national identities matter is that it creates a useful fiction by which certain groups can be oppressed or otherwise taken advantage of. The US army goes around the world acting in the best interests of many wealthy business owners. The soldiers doing their bidding don't come from those wealthy families, they come from lower classes who view their involvement through the lens of nationalism...they're serving their country. It would be one thing if those wealthy business owners footed the bill for the massive military spending that's representing their interests around the world. But that burden falls largely on the country's middle class while those with the most wealth exert influence to reduce their tax burden. This may seem like it just describes the US, but it's equally true of the situation in some other countries. Russia's involvement in the Ukraine and Syria is equally carried out by its poorer citizens at the behest of those who will make billions off those wars. And while China has managed to steer clear of active engagements much more so than the US or Russia, their military still protects the interest of their ruling class much more so than it does the interests of the lower classes who inhabit its ranks. So while everything you've said is true, it's also important to have this conversation to better recognize when these tendencies towards tribalism are being abused by those that understand them. Yes, our natural tendency is to seek a simple heuristic that separates an us from a them and to adjust that heuristic in response to the things that threaten us. That simple formula has worked well over the majority of human history. But as our social structures have become increasingly complex, it stops working well for those that aren't actively exploiting it.