There is without doubt a strong movement within Catalonia for secession from Spain. Regional leaders, now Carles Puigdemont and before him Artur Mas, have claimed that they have a democratic mandate from recent elections and now the disrupted referendum.

But do they? What is the democratic argument in the matter?

Whether or not there is an electoral majority in Catalonia for secession is not clear. If there is, it is at best a small majority, with a large minority remaining in favour of Catalonia staying within Spain. Is a small majority, if there is one, enough for a democratic mandate for so large a move?

Two main rules of democracy are:

• in the end, the majority decides,
• in so doing, the majority has a duty to respect the interests of relevant minorities.

Democratically, the question of whether Catalonia remains a part of Spain or leaves the union is to be settled by a majority. But which majority?

People who live in Catalonia have an interest in the matter. But so do the people who live in the rest of Spain. If Catalonia were to secede, the remaining Spain would be a different country. The relevant constituency in the matter, then, is all Spanish people. Even a majority in Catalonia is a minority in Spain and can have no democratic right to change all of Spain. This principle was recognised, for example, in the 2014 Scottish referendum on independence. The right to hold that referendum was constitutionally given to Scotland by the British Parliament (in what is known as an ‘order in council’) after negotiations between the British government and the regional Scottish one.

Catalonian pro-secession leaders may be right that they have a democratic mandate of sorts. But if so, the mandate is only to seek secession. There is no democratic mandate for people in Catalonia on their own to decide on an important matter that effects all of Spain. For a Catalonian referendum, for example, to be democratically valid, the rest of Spain, as in the British case, must, at the least, have conceded to Catalonia the right to hold a referendum and agreed to abide by its majority.

How strong, then, is the mandate? Since there is (at least) a large minority within Catalonia against secession, the mandate for secession must be said to be a weak one. The minority has a right to have its interests respected. The question of independence is one of great principle. A small majority in a population hardly has a right to simply impose its will on a large minority in an important matter. The mandate to seek secession, if there is one, must contain a duty to persuade the doubters. Before Catalonian leaders could argue the case for secession with force in front of the rest of the Spanish population, they would need to show that they have at last a solid majority in their own population behind them.

The strength of the mandate is influenced, further, by the reasons that are given in favour of secession. In a founding text, the American Declaration of Independence, it is stated ‘that Governments long established should not be changed for light and transient Causes’ and that the ‘Right to throw off such Government’ arises only as a result of ‘Abuses and Usurpations [and] a Design to reduce them under absolute Despotism.’

The Spanish union is long established. The government is democratic and no group or province within Spain is under despotism. From the Catalonian side, it does not seem that strong arguments are given for secession, and certainly nothing of the kind suggested in the American declaration. It seems mainly to be a case of resentment. It is said within Catalonia that the relatively wealthy province is being forced to subsidise poorer areas in the country. But that kind of redistribution is standard in a well-governed country and obviously nothing like despotism.

However, the Catalonian leaders may still have a democratic mandate to seek independence. They therefore represent a minority within Spain with a valid interest in a vital matter. The rest of Spain therefore has a duty to respect the interests of that minority. One way to do that might be to negotiate with Catalonia for a different constitutional settlement.

But, again, if such negotiations were to result in proposals for a radical centre-provincial realignment, the democratically relevant constituency for ratifying the realignment would be the entire Spanish population, for example as represented in the national assembly, the Cortes.