DEMOCRACY is no defence against terror. Recent Spanish history seems to have got everything right. An exemplary democracy, born in peace and quickly nourished to maturity, has achieved an economic miracle as a model member of the European Union. The country’s judicial system has set world standards in the pursuit of human rights. The Constitution has been hailed as a blueprint for making pluralism workable. Yet still, the bombers yesterday carried out one of the worst terrorist attacks in the country’s history.

In Palestine or Northern Ireland, you can hope for political solutions to terrorist problems, because there is something to negotiate about. In Spain, Eta killings seem pointless because the Government has nothing to offer. The Constitution is already lavish with self-government for the Basque region.

Of course, terrorism is only partly political. Eta includes psychopaths and outright professional criminals for whom violence and extortion are ways of life. But ingrained features of Spanish politics make the problem worse.

First, the much vaunted Constitution does not work. When the system of autonomous regions was introduced in 1982, I hailed it as a pattern for Europe’s future. I was wrong. Spaniards called it a Constitution of “coffee all round”. Anyone who has been to a Spanish bar will get the joke: the waiters all shout simultaneously from different directions (“A coffee here!” “Two cognacs, double-quick!” “Two beers, one fino and a ham sandwich!”). The kitchen is baffled by the conflicting demands, so it takes the easy way out: “coffee all round!”

The Spanish Constitution, like the kitchen, did not want the loudest and most intemperate demands to seem to have succeeded — so it delivered regional autonomy all round.

Historic nations, Basques and Galicians, would have a similar status to newly invented regions such as “Cantabria” and “the Community of Madrid”. If the British Government goes ahead with plans to extend devolution from Scotland and Wales to English regions, the UK will have a comparable system.

The Spanish set-up was flawed. A sliding scale of autonomy gave regional government in Catalonia and the Basque country hugely enhanced powers. The newly created regions rapidly developed robust identities and introspective elites, more concerned to enlarge their powers than to co-operate nationally. “Devolutionary inflation” set in as political powers seeped from the centre to the periphery. It has become increasingly difficult for the State to collaborate with the regions on budgets, tax, educational policies and relations with the EU.

The most dangerous part of this fractured system is that terrorists can widen the cracks. The Basque government — while maintaining a lofty moral tone — has shamefully exploited the threat of Eta. The main Basque ruling party has tolerated what are in effect terrorist-run enclaves, and adopted ever-more stridently nationalist rhetoric, to wring concessions from Madrid. An opposition party in Catalonia has conducted direct negotiations with Eta to exempt Catalans from Eta killing sprees.

Meanwhile, the central Government has become the prisoner of a dogma of its own. The inviolable unity of Spain is a shibboleth of metropolitan Spanish politics. Refusal to compromise with terrorism is a hallowed mantra.

The trouble is that the Government interprets these traditions as ruling out a referendum on the future of the Basque country. Properly conducted, among all who call themselves Basques, as well as all who live in the Basque provinces, such a referendum would produce a resounding majority for continued adhesion to Spain. It would not, of course, bring terrorism to an end, for terrorists do not respect democracy; but it would make it morally impossible for the Basque government to go on playing its opportunist game.

Instead, Spain released a spider to catch a fly. The Spanish government wanted American help in defeating Eta; so it supported an unjustifiable war, against an irrelevant enemy in Iraq. The result is a doubled threat. Now, just when Eta was failing, Spain faces a real axis of evil: the day after the hundreds were killed in Madrid, it is impossible to say for certain whether the bombers were Basque terrorists, or the new fanatics believed to have infiltrated the country from the Middle East.

Could similar killings happen in Britain? The Prime Minister seems anxious to alert us to a grim fact: his policies, like those of his Spanish counterpart, have helped to bring us all into the front line of the War on Terror and, therefore, of terror’s war on us. The IRA shows no present appetite for renewed campaigns, but terrorist groups are liable to internal splits: indeed, an Eta splinter cell may have planted yesterday’s bombs.

Britons and Spaniards think they are unlike each other; that is one of the many things they have in common. I know, I am half Spanish, half British, and it never makes me feel particularly schizoid.

History and geography give the two countries similar profiles: multinational monarchies on Europe’s margin. Atlantic outlooks, maritime destinies and imperial pasts have often brought Britain and Spain into conflict but have also been sources of common experience.

Mutual understanding should come easily — especially now, to near neighbours, facing common problems, under a common threat.

The author is a professor of history at Queen Mary, University of London

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