Nationalism fragments and weakens - Can Spain survive Catalan vote?

Sometimes the best way to understand reality is to indulge in fantasy. So, try to imagine what the Irish and British governments — and Stormont if it can stir itself — might do if Sinn Féin were to organise an unofficial vote on Irish unity in the North. 

If population trends continue as they are, then the prospect cannot be ruled out.

How might the population of this Republic respond to an event it could not control but one that would have a profound impact on its prospects? How would Unionism react? Probably in a way that would make yesterday’s street violence in Catalonia seem a party in the Playa del Bogatell sunshine.