The EU countries may be right that Catalonia is legally a matter of Spanish constitutional law. But they should also be frightened. Catalonia is Europe’s problem.

The imprisonment on remand of eight Catalan politicians, on blatantly political charges, and the Belgian asylum sought by its president, appears to be an engineered confrontation.

Two days ago, the Madrid government reneged on an agreement that it would not suspend the Barcelona government if it did not declare independence and agreed to new local elections next month. Madrid then proceeded with suspension, and Catalonia duly proceeded with declaration – though with no mention of implementation. Madrid immediately arrested those Catalan politicians (and officials) it could find, on charges of rebellion and treason.

So far, so absurd. No poll has yet delivered a clear majority of Catalans for independence. Barcelona has proceeded within accepted democratic norms and without recourse to violence – unlike Madrid in the government’s efforts to stop the recent referendum.

Never in the long and far bloodier fight of the Basques for independence was the Basque leadership ever imprisoned. Catalonia now faces an election next month with the prospect of its entire independence leadership in prison.

Catalonia is being watched, with varying degrees of intensity, by Basques, Bretons, Flemings, Scots, Bavarians, Silesians, Ukrainians, Transylvanians, Venetians, Corsicans and others. Its struggle resonates among increasingly nationalist Poles, Bohemians, Hungarians and Greeks, across Europe’s patchwork of regional sensitivities and long-harboured grievances. Old feuds are rekindled and jealousies revived. Hypocritical Britain cannot talk. It long opposed Irish separatism and denied devolution to Scotland and Wales, while it sent soldiers to aid the break-up of Yugoslavia.

It is hopeless to seek recourse from these woes in statute books and legal niceties. Self-determination has been the essence of Europe’s stability since Woodrow Wilson’s 14-point programme for Europe’s future in 1917. How such determination is defined may be moot: what of the self-determination of Spaniards against that of Catalans? But it is in Europe’s interest to seek that definition, to formulate protocols whereby separatism can be resolved into grades of autonomy. European statehood has long been a “vale of tiers”.

Since the EU itself is inherently centralist, it makes sense for the Council of Europe, the 47-nation organisation which deals with democracy and human rights across the European continent, to undertake such a task, urgently. The EU has worked itself into a political straitjacket, such that few of its member nations would dare hold a referendum on continued membership. This cannot be healthy for the EU or for Europe. The rising tide of identity politics is now the greatest threat to Europe’s free development. Catalonia is not a little local difficulty. It is an awful warning.

• Simon Jenkins is a Guardian columnist