Comment: Many European states really should acknowledge the need for greater federalism.  The monarchic age in European history saw kings cobble together vastly disparate holdings with little regard for the local populations.  Many of those imperial states disintegrated in the 20th century (e.g, Austria-Hungary, an enormous union of a dozen or more major ethnic groups with nothing in common beyond that the Habsburgs had managed to acquire their land at some point), but others didn't, and the advent of greater democracy didn't obviate the centralizing, dominant culture of the central state.  I don't think Catalonia has any issues that couldn't be addressed to most people's satisfaction through devolved constitutional status.