The European Commission (funnily enough through ex-PSOE leader Joaquin Almunia) said that he thought a new separate Catalonia would not stay part of the EU. His argument is that since the basis of the EU is a set of bilateral treaties that Catalonia is not a party to (only the Kingdom of Spain), Catalonia wouldn’t be able to claim any rights based on those treaties.
Of course, treaties can be changed, but given that joining would require unanimous approval by the other EU members (including Spain), one only needs to have a look at the list of active separatist movements in Europe to see that this is a can of worms that no one really wants to open up.
The alternative would be something similar to what Scotland is hoping for (but may not get the chance to vote for), which is devolution-max, where everything except defense and foreign relations would be handled by the Scottish government. Of course, that requires a constitutional change and a cooperative central government.
This is why I think the arguments about independence are a complete waste of time. If the rest of Spain doesn’t agree, nothing is going to happen. Since the EU includes Spain plus a bunch of other countries that don’t want to encourage their own separatist movements, nothing is going to happen at the EU level either.
One additional reason that I think nothing is going to happen is that the political leaders here all lack the guts for any kind of civil disobedience that could legally endanger themselves. If Artur Mas really believed in his cause, he should just announce a referendum without permission from Madrid and challenge them to send the Guardia Civil to arrest him for it. “I am Sparticus!”
Now that I would have some respect for.