Catalonia unilaterally declared independence without the permission of Spain. There is a long and historical debate as to when a region of a country can “secede” and become independent. I won’t enter into that history here but simply note that this situation is very different from the Scottish attempt to become independent through a referendum a few years ago. Then, the referendum was authorised by the UK Parliament and if it had been successful, the UK Parliament would have (likely) not stood in Scotland’s way to become independent.
In this case, everything Catalonia has done has been unilateral and against the express wishes of Spain; its sovereign.
In international law, the so-called principle of self-determination says all peoples have the right to self-determination but ordinarily in the case of a region within a country, that is limited to self-government. There is a debate whether if the country prevents self-government, especially through military force, it might have the right to claim independence. Despite some evidence of Spanish police force at the time of the referendum, there is nothing to substantiate this (yet).
The International Court has been very clear that declarations of independence – of themselves – are not prohibited by international law (Kosovo Advisory Opinion 2010). But whether they result in a successful independent State is another matter. That largely depends on recognition – and in this case, countries such as the US and the UK have been very quick to refuse it.
So is Catalonia a State? Well, in the absence of recognition by any other State and clearly still subject to Spanish control, it is quite difficult to see how the fourth Montevideo criteria of “capacity to enter into legal relations with other States” (ie political independence) has been met.
Could things change? Yes.
Spain might eventually agree to Catalan independence – this is highly unlikely. And once Spain does this, other States will follow.
Catalonia and Spain may enter into a civil war – let’s hope not. But eventually some States may as a result recognise Catalonia.
Spain may act so harshly towards Catalans now that international sympathy begins to emerge for Catalonia as a State – this is sometimes referred to as “remedial secession”; that the only way out for Catalonia is independence. Unlikely in this situation.
Ironically, the best way for Spain to keep Catalonia within Spain is to give it even more autonomy. But will it?