Eta's actions in recent weeks have provoked revulsion throughout Spain, far beyond the confines of San Sebastian. Campaigning for the country's general election, which takes place on 3 March, has been interrupted twice in two weeks as political leaders of all colours attended the funerals of two prominent figures shot dead by Eta marksmen. The socialist lawyer Fernando Mugica was assassinated at lunchtime in one of San Sebastian's handsome streets, and the judge Francisco Tomas y Valiente was picked off last week in his study at the university in Madrid. That second killing fuelled the fear and anger of Spaniards, and led to a million people marching in protest through Madrid behind their prime minister, Felipe Gonzalez. Eta has been seeking independence for Euskadi, or the Basque country, since 1960 and has survived both the repression of the Franco years and the undercover hit squads which have been active during 20 years of democracy.
Madrid has tried everything, even granting the Basques the greatest degree of autonomy enjoyed by any region in Spain - indeed in Europe - to defeat Eta. The region has its own police and raises its own taxes. But far from buckling under force, or yielding to concessions, Western Europe's last remaining home-grown guerrilla army shows every sign of being stronger and more intransigent than ever.
Even before last week's horror, the anti-terrorist fight was the hottest issue in Spain's election campaign because of the Socialist government's role in a dirty war waged against Eta in the early 1980s by the illegal Anti-Terrorism Liberation Groups, Gal.
The scandal that has been swirling around Felipe Gonzalez for months reached a peak in January, when the Supreme Court accused the former interior minister, Jose Barrionuevo, of having masterminded the Gal, which kidnapped and murdered more than 25 people, many of whom had nothing to do with Eta but were simply cases of mistaken identity. Mr Gonzalez denies all knowledge and the judges are still deciding whether to call him in for questioning.
Many of the operations carried out by the Gal, and by the Gal's shadowy predecessors under the previous centre-right government, were bungled, especially the one pinned on Mr Barrionuevo: the kidnapping in 1983 of the Frenchman Segundo Marey, who was held even after his kidnappers realised they'd got the wrong man.
Many Spaniards privately feel that any methods were probably justified against Eta. Both socialists and conservatives are calling for la mano dura, the tough line, that could include outlawing parties such as the pro-Eta Herri Batasunaand its radical youth movement, Jarrai. But many Basques doubt this will help and say that in the end dialogue is the only solution.
"Eta will not be defeated by more policing," says the region's spokesman for the conservative Basque Nationalist Party, Joseba Equibar. Speaking in San Sebastian days before last week's attack, he said: "We've reached a state of infinite deadlock. Eta cannot defeat the Spanish state, but the state cannot crush Eta."
Anti-Eta security measures, always in place, have tightened to the maximum in the wake of a devastating bomb attack that killed six civilians in Madrid last December, and amid the persistent harrying of Basque peace demonstrations by Jarrai street gangs.
But if a band of gunmen identified by witnesses shoot a man dead in a city street in broad daylight, elude police checkpoints and disappear from view after abandoning two getaway cars - one after a crash, the other after a puncture - this suggests not so much shoddy policing as the existence of a social infrastructure which gives the terrorists protection and shelter.
This is not to say that Eta enjoys wide popular support. Votes for the pro-Eta Herri Batasuna are in decline and now stand at around 15 per cent in the region. However, many Basques support Eta's nationalist aims while deploring their violent methods. In addition, many Basques are afraid. In a close, largely rural community, pressures can be put and reprisals threatened if support or shelter are not granted.
What is it about these 2.8 million Basques who have defended their independence so fiercely down the centuries and whose extraordinary language predates other European tongues and is unlike any other on earth? Renowned for their strength and size, they were never subdued, even by the Romans, who left them alone in exchange for free movement between Gaul and Hispania.
The Basques kept to their forests in their tight valleys and steep hills. Even when France chopped off part of their northern territory, and successive dynasties in Madrid carved out chunks to the south, they held on to ancient liberties and elements of sovereignty until Franco stripped them away after pulverising the historic town of Guernica in 1937.
Particularly punished were the northern provinces of Viscaya and Guipuzcoa, which held out for the republic, and it was here that Eta emerged and where its base remains strongest. But here counter-demonstrators have established themselves, taking to the streets of San Sebastian several times a week in solidarity with two hostages held by Eta, the businessman Jose Maria Aldaya and the prison officer Jose Antonio Ortega Lara. The streets are adorned with pro-Eta graffiti; families of Eta prisoners are on hunger strike in the cathedral crypt and pro-Eta youth groups fling stones and insults not only at peaceful protesters demanding the freedom of Aldaya and Ortega but at youngsters with their fathers enjoying a Saturday afternoon sports festival.
There is, according to Cristina Cuesta, a San Sebastian peace campaigner whose father was killed by Eta gunmen in 1982, "a constant indirect confrontation that floats in the atmosphere". In the small villages and ugly industrial suburbs, confrontation and fear can be even sharper.
One night in 1984, a former policeman, Mikel Sueskun, long gripped by the ideal of an independent Euskadi, extended a comradely hand to a pair of Eta members who sought a safe house for the night. His action cost him a 60-year sentence for "collaboration with an armed gang".
Sueskun, now 48, served more than six years, the equivalent of 13 years with remission earned by working and studying law. He now enjoys "third- grade imprisonment", an open custody that allows him freedom during the day and at weekends. "I agreed to shelter them for a night, but they came back, stayed a weekend, then another week," he remembers. "A few days later, they were implicated in the murder of a policeman, and my name was mentioned."
He was picked up in 1989 by his former colleagues in the Basque police, the Ertxaintxa. "I'm sure my sentence was harsher because I was an ex- policeman." He returns to Nanclares prison in Vitoria at night and is awaiting the act of pardon that would give him freedom.
Sueskun was among up to 30 Eta prisoners who promised to renounce violence in exchange for early release and "reinsertion" into society. "I can't say I wish it had never happened, but it was a mistake," he says of his crime. He had been in contact with Eta since the Seventies and became close to them around 1983.
He was lucky to serve his sentence in prisons near his home. Some 540 of more than 600 Eta prisoners are dispersed throughout Spain in a deliberate attempt by the government to break their formidable solidarity and get them to recant and opt for early "reinsertion".
One of Eta's principal demands is that their prisoners be brought nearer home. The organisation says the attempt to break their spirit has failed and that prisoners have a constitutional right to serve their terms near their home and families.
This demand motivated Eta's decision to kidnap Ortega Lara, an officer at Logrono prison, last month, and probably lay behind the killing of Fernando Mugica, who was a strong advocate of the policy of dispersal and whose brother, Enrique, introduced the practice when Justice Minister from 1988 to 1991.
Sueskun remains committed to Basque independence and self-determination, and shares the beliefs of Eta and Herri Batasuna. "But I can't support their methods. I'm in prison for defending the rights of a people. I want the independence of Euskadi but only if the majority want it."
This is a view shared by Jose Maria Montero, a Bilbao lawyer and former MEP for Herri Batasuna. He spent years defending Eta prisoners and and helped establish links that led to doomed talks between Eta and the government in Algeria in 1989. "Unlike in Sinn Fein, where a leadership has matured over 25 years, in Eta over the same period the leadership has been renewed five or six times, each time becoming more extreme and more remote from the real world," he says. Mr Montero is convinced Eta will consider conversations with Madrid only from a position of strength, defined in military terms.
"Eta believes the contradictions of the armed struggle can be solved only by armed struggle, action for the sake of action. Their leadership has become intoxicated by its own dogma. But I'm afraid the extremist forces it has unleashed will escape its control like the sorcerer's apprentice and we'll have an explosion."
Mikel Sueskun notes that many Eta members come from the Jesuits, founded by the Basque Ignacio de Loyola, whose seminaries "hold the Basques' written history and tradition". He muses: "I have always led a disciplined life. I was seven years in a Jesuit seminary, then two years doing military service, then I served four years in the police, and more than six years in prison. Discipline is good, it makes you treat people with respect. But sometimes it freezes your heart."
If Mr Gonzalez loses on 3 March, it will be largely because of Gal's anti-Eta skulduggery laid at his door. But uncertainty will remain about whether an incoming Conservative government can offer anything to prevent the Basque country from slipping towards civil war.
Bloody struggle for Basque independence
1960: Eta founded by students to fight for independence and self-determination of Basque people. Responsible for more than 800 deaths since 1968, including 20 national or local political figures
1961: Eta attempts to derail a train taking Francoist veterans to a rally in San Sebastian. Police arrest and torture more than 100 Eta suspects
20 Dec 1973: assassination of Luis Carrero Blanco, prime minister and Franco's designated successor, prompting the collapse of the dictatorship
Oct 1979: Jose Mara Uriarte Alvain, mayor of Bilbao, killed
1980: Eta's bloodiest year - 118 killed
30 Sept 1980: Jose Ignacio Ustar, of the conservative UCD executive committee, killed in Vitoria
23 Feb 1984: Enrique Casas Vila, Socialist senator, shot dead in San Sebastian
12 June 1985: army colonel and his chauffeur killed in Madrid on day Spain signs EC membership deal
25 April 1986: five Civil Guardsmen killed by car-bomb
14 July 1986: 12 Civil Guardsmen and 56 people hurt in truck explosion in Madrid
1986: Contacts established between Eta leader Txomin Iturbe and government
1987: Txomin killed in Algeria. Eugenio Etxebeste "Antxon" emerges as new interlocutor and contacts resumed
19 June 1987: bombing of a supermarket in Barcelona kills 21 and wounds 35
1989: Ceasefires announced as Eta-government discussions take place in Algeria. But disagreements lead to breakdown of ceasefire
6 Feb 1992: car-bomb in Santander kills three
15 Jan 1992: ex-UCD senator and minister Manuel Brosta Pons killed in Valencia
1992: Spanish government arrests in France Eta's entire leadership
21 June 1993: six soldiers and a civilian killed in car-bomb attack in Madrid
29 July 1994: three people, including a general, killed in the centre of the capital
23 Jan 1995: Gregorio Ordonez, provincial leader of Popular Party in Basque country, shot dead in San Sebastian
19 April 1995: Jose Maria Aznar, PP national leader, escapes car- bomb attack
10 Aug 1995: Police foil plot to kill King Juan Carlos
11 Dec 1995: Six die in car-bomb attack in Madrid
6 Feb 1996: Basque Socialist leader Fernando Mugica shot dead in San Sebastian
14 Feb 1996: Francisco Tomas y Valiente, ex-president of constitutional court, shot dead in his study at Madrid UniversityReuse content