What are the immediate consequences of a unilateral declaration of independence? And what needs to happen for it to be recognised and for Catalonia to then be considered an independent state?
"The existence of a new state is dependent on facts: that there is a territory and a population governed exclusively by one government," Jose Antonio Perea Unceta, professor in international law at the Complutense University of Madrid told The Local.
"As such, Catalonia would be a state as soon as the Spanish government withdrew its armed forces, police, judges, treasury inspectors etc from the territory. A declaration of independence does not create a new state. It's a political act."
"A unilateral declaration of independence only has legal weight if it is successful in creating a new sovereign power that is not subject to any other, and is accepted by the population initially, then other states afterwards," explains Josep Costa, associate professor in political theory at Barcelona's Pompeu Fabra University and a licensed lawyer.
"Politically speaking it's the act of creating a sovereign power. From the judicial perspective it's the act of establishing a new legal system. The consequences depend on its content (the rules it establishes) and above all the efficiency or effectiveness the application of the new legal order have."
"On top of judicial questions, it's a factual matter: do you, as a Catalan state that has declared independence, have the judicial, administrative and coercive capacity to rule over your citizens or not? Will you have the capacity to resist the certain repressive action of the Spanish state or not? That's the issue," adds Joan Vintró, lawyer and lecturer on constitutional law at the University of Barcelona.
Catalonia's regional parliament. Photo: Lluis Gene/AFP
How important would international recognition of a new Catalan state be?
"It's always important, but before international recognition the most important thing is internal effectiveness. International recognition can take a while or not, and it could be major or minor, but the conditions for a state to be independent aren't really that it's recognised internationally, but rather that it's recognised internally by the citizens it has to manage and impose law upon," Vintró argues.
"So the issue with a unilateral declaration of independence isn't really international recognition – of course it helps – but what's more important is that citizens of this new state recognize the new power as theirs. Do they pay taxes, do they respect the institutions put in place, and do you have a state with all the elements of state power, capable of consolidating itself?"
Professor Perea Uncenta also sees international recognition as of lesser importance:
"Recognition from the international community does not create a state. It's a political act. It is the case that there are entities recognized by more than a hundred states that are not technically states, like Kosovo, because in that case the government is for the moment subject to the United Nations. Others, like Somaliland, have not been recognized but factually are already states because they have a population and territory they govern over – and do so without the interference or dominion of other states."
One possibility being touted is the so-called 'Slovenian option', which would mean declaring independence but with deferred effect subject to the possibility of international mediation. Why would Puigdemont want to do that?
"The key to that isn't legal, it's about knowing if a declaration of independence made on those terms can have advantages at an international level – above all if during the period in which it has not entered into effect some kind of negotiation is established," Pompeu Fabra University's Costa notes.
"It's not legally advantageous, but politically it is. In the Catalan case it has some practical inconveniences, because the Spanish government will presumably not respond with genuine negotiation."
The University of Barcelona's Vintró – who was previously a member of a body created to advise the Catalan government on possible processes of transition to independence – sees that approach as a way of buying time for the regional government:
"On the one hand you're not renouncing your objective and don't disappoint your supporters – the government and parliament doesn't feel it can ignore two million people going out and voting in difficult conditions and feels it is obligated to show it is continuing towards its objective. On the other, you're conditioned by present circumstances not making it viable for independence to happen immediately."
"So you say 'we're not giving up, we're continuing forward, but we're appealing to the international community to act as a mediator and convince the Spanish state to agree to a referendum with legal guarantees'. It's a way of not renouncing your objective while creating waiting time, within the margin of which you can negotiate on different fronts to either make independence effective from a certain time, or submit to a legally guaranteed referendum," he adds.
But international law expert Perea Unceta is not convinced that the 'Slovenian option' could work for Catalonia:
"It involves a symbolic declaration, international mediation, then later, recognition of the failure of negotiations, and requires some elements not present in the Catalan case. There is no armed conflict in which the UN, European Union or OSCE is mediating to stop, and there is not the withdrawal of a federal administration such as Belgrade did in 1991 after the failure of the Brioni Agreement."
The Brioni Agreement was a document signed by representatives of Slovenia, Croatia and Yugoslavia with European Community (EC) mediation that attempted to create further negotiations on Yugslavia's future, and effectively ended the further federal influence of the Yugoslav government over Slovenia.
Ljubljana, Slovenia. Photo: Jure Makovec/AFP
The Spanish government has suggested it is prepared to invoke article 155 of the country's constitution and suspend Catalan autonomy in response to a declaration of independence. Would that immediately annul the independence declaration? What would the result of using the article be?
"It's almost certain they will do that. The Spanish state has practically no other alternative, other than to dissolve Catalonia's institutions – a measure not included in article 155 and that would likely be unconstitutional – if independence is declared," Costa predicts.
"Applying article 155 would annul a declaration of independence in the same sense that the Constitutional Court annulled the calling of a referendum. By that I mean that decisions on paper have to be executed in practice afterwards, and it's not clear that the Spanish state has the capacity to effectively suspend autonomy and block the Catalan government from continuing to operate."
The University of Barcelona's Vintró is not so sure the Spanish government will invoke the article however, a measure he describes as 'very serious':
"If a formal declaration with a written text is made then I think the Spanish government will do what it has always done and go to the Constitutional Court and wait for it to suspend the declaration. That would be the first action. The thing about article 155 is it's a very serious reaction that has never been used before and doesn't have previous legislative development to consult, so it's not really known what measures would be adopted".
"One important thing about article 155 is it's designed to always be applied temporarily: you can't dissolve Catalan autonomy without changing the Spanish constitution. So the further measures that could be imposed upon the Catalan government (because let's not forget, measures have already been imposed) are required to be temporary. You don't solve the problem, you impede the independence process, but you don't resolve the political problem. Even if elections in Catalonia are forced, you could end up back in the same place as it's entirely possible the pro-independence parties end up in the majority again," he concludes.
Regardless of what happens in Spain over the coming days then, it looks like the conflict is destined to drag on further.