CAN a terrorist organisation ever be wholly defeated? The British government’s willingness to bargain with the Irish Republican Army suggests that only long negotiations can bring violence to an end, and even then it can flare up again. Yet in Madrid, they think otherwise. The deadly First of October Anti-Fascist Resistance Group (Grapo) that emerged from murky 1970s Maoism has ceased to be a threat, and its members are in jail. Could that happen to the separatists of Basque Homeland and Liberty (ETA), Europe’s last big domestic terror group?

A much-weakened ETA has done a lot to wean itself off violence. It has not killed in Spain for four years. In October 2011 it unilaterally declared a permanent ceasefire. Those who called it remain in control. But ETA still has arms and explosives, probably buried in waterproof containers in French forests. A heated debate continues between ETA’s leadership, its 700-odd jailed members and its political allies over whether to give up the weapons.

Many Basques want the Popular Party (PP) government led by Mariano Rajoy to offer ETA a carrot, but it refuses. A highly vocal “victory or nothing” PP lobby, backed by influential newspapers, is often blamed. Instead, the government demands that ETA must accept defeat. “Either they dissolve themselves, hand over their arms, apologise and recognise the harm they have inflicted, or the rule of law will dissolve them, leaving them as an inoperative acronym, like Grapo,” insists Jorge Fernández Díaz, the interior minister.

ETA’s leadership was expelled from its sanctuary in Norway earlier this year. David Pla, Iratxe Sorzabal and Josu Ternera, the three ETA heavyweights leading the peace process, are tough negotiators. They would love to get a deal that helps prisoners, either through early release or with a relaxation of rules that keep many in jails far from their families. But government obstinacy means “peace for prisoners” is unlikely. Sortu, the non-violent separatist movement that emerged in 2011, may have to drag ETA towards peace yet again.

That would be welcomed by Madrid, but government stubbornness carries risks. It sidelines the regional prime minister, Iñigo Urkullu, and his moderate Basque Nationalist Party (PNV). Mr Urkullu is furious that the PP government has failed to ease ETA’s journey to disarmament. And he is worried by Sortu, whose electoral arm, EH Bildu, won a quarter of the vote in the Basque elections last year, coming second to the PNV. If EH Bildu ever unseated the PNV, separatism would dominate local politics, just as it does in Catalonia. Yet Basques already enjoy considerable political autonomy and, though most voters back nationalist or separatist parties, fully half oppose independence.

By staying out of the negotiations, the government gives ETA more control. If disarmament comes, ETA is likely to choose between handing arms to a group of experts in the Netherlands already involved in the process, or delivering them to the Basque regional police. But Spanish and French police would have to stay away, requiring at least a silent nod from Mr Rajoy.

EH Bildu’s incursion into everyday politics forces it to confront such mundane issues as rubbish collection and planning laws, which affect Basques’ everyday lives, rather than dreaming of independence. That engagement can only be good. But with ETA in the wings, politics can never become normal. Everybody should want it to leave the stage completely.