In Madrid on Friday, Spain’s cabinet agreed to exhume the remains of the fascist dictator and civil war victor General Francisco Franco. Their decision should not be dismissed as merely some macabre footnote that is of interest only to historians. On the contrary, the cabinet’s action is a live political decision that is pregnant with wider meaning for the development of modern democratic Spain.

While it may be physically straightforward to remove the remains from the tomb where they have lain since Franco’s death in 1975, the exhumation will in every other respect be fraught with complications and significance. Pro-Franco demonstrations at the site after Friday’s decision are likely to be repeated. Meanwhile, Spain’s minority Socialist government under Pedro Sánchez will use the decision to enhance its own authority on the left in the volatile political atmosphere that has persisted since the financial crisis of 2008-09. And Spain’s decision will cause reflection well beyond its borders too. For it is a reminder, if one is needed, of the never-ending importance – and sensitivity – of historical memory in the continuing evolution of every modern nation state, including Britain.

Spain’s dictator from 1939 to 1975 was buried in the basilica that forms part of the monumental, fascist-era Valley of the Fallen memorial, north of Madrid. Franco conceived the memorial, on which work began in 1940, as a “national act of atonement” following the civil war of 1936-39, which he began with a military coup in north Africa against the elected Republican government. Up to 40,000 civil war dead from both sides in the conflict are buried at the site. Many of those who worked in the memorial’s construction were political prisoners; several died during the project. Although the memorial was ostensibly conceived as a shared site, it has always been seen on both sides as a nationalist shrine. Franco’s own interment there – the only person buried in the valley who did not die in the civil war – emphasised that meaning still further. Pro-Franco demonstrations still occur there, in spite of a ban.

After Franco’s death the memorial and tomb were allowed to remain intact as part of the “pact of silence” on the civil war that was agreed between the parties of the right and left during the transition to democracy. But since the start of this century there has been growing pressure for change from civil society. In 2007 a Socialist government passed a historical memory law which began to reopen issues connected to the civil war and formally condemned the Franco regime. Now comes this week’s decision to remove Franco’s remains and to begin rethinking the nature of the Valley of the Fallen as a truly shared site. As Spain’s deputy prime minister, Carmen Calvo, put it after Friday’s decision: “Democracy is not compatible with a tomb that honours the memory of Franco.”

This will not be easy. Spain’s rightwing parties may have long ago moved beyond Francoism, but they remain the natural political home of many who regret the modernisation of Spain, the growth of regional autonomy, the decline of the Catholic church (which backed Franco relentlessly) and attempts to rewrite the nationalist version of history. Yet there is no getting away from the facts concerning Franco. The war he launched against a democratically elected government in 1936 was intended, as a fellow general said, to eliminate “without scruple or hesitation those who do not think as we do”. The civil war killed some 200,000 combatants, with at least a further 200,000 murdered extra-judicially or after sham trials. At least 20,000 Republicans were killed after the war ended, while many others died in prisons and in slave labour.

Pointlessly refighting old wars has no value. But exhuming Franco is a necessary step in the final stages of Spain’s historic journey away from authoritarian violence towards enduring democracy. Mr Sánchez is taking a political risk. But this decision is not just about bringing justice to the families of those who suffered under and because of Franco, important though that it is. It is about asserting the vibrancy of a more pluralist Spain in a more pluralist Europe. It is about the present, not the past.