Following Spain's transition to democracy in the 1970s, Catalan nationalism was marked by moderation, caution and gradual progress. The Catalan movement has eschewed separatism in favour of a plural and decentralised vision of Spain, itself anchored in Europe.
What, then, explains the polarisation of the last few years and the confrontation seen last weekend between a nationalist movement determined to hold an independence referendum and a Spanish state determined to stop it?
This is a tale of missed opportunities, a lack of dialogue and a disappearing centre ground.
The Spanish constitution of 1978 represented a compromise between centralist forces from the Franco regime and nationalist and regionalist forces on the periphery.
It declared both the indissoluble unity of Spain and the right to autonomy of the “regions and nationalities” that compose it, while carefully avoiding defining what a nationality is.
Catalans could live with this formula but hankered after a recognition of their own distinct status as a "nation" (like Scotland in the UK), especially after some other regions declared that they too were "nationalities".
Another complaint was about provisions in the autonomy law that allowed Spain to set restrictive frameworks in devolved matters. So a part of the school curriculum is set by Madrid and the rest in Barcelona, a very sensitive matter.
A third issue concerned finance. Catalonia contributes heavily to the Spanish exchequer. It has expanded its own taxation powers but this falls short of the provision that allows the Basque Country to collect its own taxes and then pass on a share to Madrid for common services.
In 2006, a new statute of autonomy was drawn up by a coalition of nationalists and socialists in Catalonia and passed by both Catalan and Spanish parliaments and in a referendum in Catalonia.
Polarisation was accentuated by the presence of weak leadership in both Madrid and Barcelona
Opponents to the statute, including the Spanish Popular Party, appealed to the Constitutional Court, which, after a long process, struck down some key provisions and subjected others to a restrictive interpretation.
The Popular Party started to use anti-Catalan rhetoric to gather support elsewhere in Spain. They even supported a provision in a new autonomy law for Andalucía that was identical to a Catalan provision they claimed was unconstitutional.
The financial crisis precipitated further arguments about finance and the scene was set for confrontation.
Polarisation was accentuated by the presence of weak leadership in both Madrid and Barcelona. The Popular Party, regaining power in Spain, reverted to intransigent Spanish nationalism. The historically dominant party in Catalonia, Convergència (now called PDeCAT) moved towards independence, lining up with the Republican Left and a far-left party, CUP.
This movement covered a wide political spectrum but united on the demand for an independence referendum. Meanwhile, both the Popular Party and Convergència were mired in corruption scandals.
Consultative referendum
Many academic lawyers in Catalonia (and some elsewhere) have argued that Spain could have found a way to have a consultative referendum by choosing the right form of words. Others favoured changing the constitution if necessary. The Popular Party, supported by many others in Madrid, would have none of it, sticking to the narrow letter of the law.
Spanish authorities could have ignored the latest vote and told their electors to stay away. Instead, they opted for physical obstruction
So, instead of having a debate about the political, economic, social and other merits of independence (as in Scotland) the argument has focused purely on the “right to decide” as a democratic principle.
Polls have shown that, while support for independence is at about 40-45 per cent, support for the right to decide is much higher.
Both sides have pursued confrontation. The Catalan government staged an unofficial referendum in 2014 but, with unionists boycotting it, this fell flat. They then called “plebiscitary elections” to gain a mandate for independence. Pro-independence parties gained a majority of seats, but not of votes.
The next step was another referendum, to be followed by a unilateral declaration of independence. This was accompanied by some wishful thinking about the prospects for European and international recognition and the task of governing and collecting taxes.
Spanish authorities could have ignored the latest vote and told their electors to stay away. Instead, they opted for physical obstruction. Public servants were prosecuted and barred for their role in the 2014 referendum. Others were arrested for organising the new referendum. Firms producing ballot boxes and papers were raided. Posters and websites promoting the referendum were taken down.
On the day, Spanish police were sent in to manhandle voters and violently remove them from polling stations.
Surveys have shown that, given the option of more home rule, recognition of their national identity and a financial compromise, most Catalans would not vote for independence. Being told that they do not have the right to do so is another matter.
Catalan and Spanish leaders appear unable to resolve this issue among themselves. The European Union lacks the means and the will to intervene. The time may have come for some better international principles about who has the right to self-determination and how.
Michael Keating is professor of politics at the University of Aberdeen, director of the Centre on Constitutional Change and visiting professor at University College Dublin.