Europe seeks to avoid the traps of nationalism and tribalism by ignoring the whole subject of defining itself.

You may be on to something there, but I don't think it works quite as you say. In fact Europeans (insofar as one can generalize, and minus a vocal minority) don't feel concerned by nationalism and tribalism (in the sense I take it you're using, of tribalism as a strong attachment and sense of belonging to one's group of origin). It's as though, having contributed to forming those concepts in history, and having particularly sacrificed at the altar of the nation, having well-nigh destroyed ourselves in two cataclysmic wars that grew out of nationalism/tribalism, we have emptied our heads of them. We are just as likely today to feel regional ties (or, as Sven suggests above, city ties), as ties to the nation-state. It may seem presumptuous, but I think we avoid the traps of nationalism, not by seeking or by conscious effort, but quite unconsciously because we have got past that point. (Yes, it does sound presumptuous, but I think there's truth in it.)

Whether that means that we may succeed in inventing something new, I don't know. We may not succeed. But there's, let's say, an open door...

(Sorry if this doesn't address the question in your diary, it's just a thought bouncing off your comment...)