One of the reasons things like the EU are a good idea, is because there are very few if any nation states e.g Basque in Spain, Northern Ireland in Ireland/UK, Scotland in UK, Shetland in Scotland, Swedish Finns in Finland and so on and so on (and it's a global thing, Kurds in Iraq/Syria/etc). It's all a bit fractal and and subjective and shades of gray and often it's the drawing of sharp artificial boundaries over the top of that that causes the problems.
One thing that unifies the extreme socialist left and the extreme and alt-right in the UK is an almost rote belief in regional self-determination, as if all of those movements could have a place of their own if wider agreements can only be broken up. The paradox of both the extreme left and extreme right is that many among them admire Putin as a "strong leader" and believe Putin is acting out of Donbas's interests in liberating them. Their shock at the disconnect with what is actually happening -- that everyone free of motivated reasoning could see coming -- is fascinating.
But there is a funny thing going on right now at great speed. For a while in Europe it has been Putin's world and we just live in it -- he's been the most sophisticated single backer/instigator of discontent across the continent. But it looks like there is a chance, right now, that this bubble could burst for him, and burst domestically. It's going to be a turbulent fortnight.