Catalonia is wrong. Madrid is right. There is a Spanish constitution which clearly lays down the sovereignty and integrity of the Spanish state. There is no provision for breaking away. Catalonia, despite its distinctive past, has long acquiesced in the Spanish constitution and has no legal right to become independent. On that point the law is clear.

The essence of the post-1945 European settlement is the integrity of states. After centuries of horrific wars, stable statehood is the rock on which Europe’s security rests. Allow old grievances to recur, old feuds to revive and old boundaries to shift, and chaos will ensue. Besides, that other rock of stability, the European Union, relies on states being able to enforce EU diktats on subordinate regions without challenge.

If only politics were that simple.

Just as the EU commission in Brussels has become a parody of the pre-Reformation Roman church, so aversion to central power is destabilising states across the continent. Economies globalise and national governments centralise, and as a result regional identities become more assertive and belligerent. Not just Catalans but Scots, Basques, Corsicans, Flemings, Silesians and Venetians show no signs of diminishing their plea for more autonomy, whether heavy or “lite”. The Catalans are merely the vanguard of a movement against the clumsy bureaucratic elites that rule Brussels as they do Madrid – not to mention London. Hence it is pointless for Madrid simply to read the rule book and the riot act to solve this crisis.

The EU is foolish to think this is none of its business. Its blundering diplomacy has already lost it the United Kingdom

It is clear that the Catalan president, Carles Puigdemont, is desperate to avoid a cataclysmic break with Madrid, knowing that his own people are deeply divided in their separatism. There has to be the sort of deal that there was with the Basques in the 1990s – perhaps even more radical. Spain is already among the most devolved states in Europe. Its recent ham-fisted treatment of Barcelona demands it become even more so, possibly with a new Catalan constitution that can be put to local plebiscite.

The EU is foolish to think this is none of its business. Its blundering diplomacy has already lost it the United Kingdom. No other nation dares hold a referendum on exit. Separation beckons from Poles, Czechs and Hungarians. The German-dominated eurozone has blighted the Greek and Spanish economies and is, in large part, to blame for the present crisis. The EU cares as little for regional identity as it does for any sort of devolution. The Catalonian question is about Europe as much as it is about Spain.

• Simon Jenkins is a Guardian columnist