ETA, the Basque separatist group, is dissolving itself, it stated in a letter published on Wednesday, closing a history that included one of the longest terrorism campaigns in modern Europe, which killed over 800 people in Spain.
Militants of ETA had been expected to make a formal announcement some time this week, after almost six decades of fruitless and violent resistance to the central government in Madrid.
Spanish news organizations reported on Wednesday that in a letter to various officials and organizations, dated April 16, the group wrote, “ETA has completely dissolved all its structures and has terminated its political initiative.”
But the letter, first obtained by a Basque journalist at the online publication Eldiario.es, insisted that the Basque conflict with Spain — and, to a lesser degree, with France — “did not begin with ETA and does not end with the end of ETA’s journey.”
The news reflected what has been evident for years, that ETA is a spent force, its ranks decimated by arrests, its popularity minimal in the Basque region along Spain’s north coast. In their long struggle, the government has won.
Founded in 1959, ETA — whose full Basque name, Euskadi Ta Askatasuna, means Basque Homeland and Freedom — began as a left-wing, student-led independence movement during the dictatorship of Gen. Francisco Franco.
It turned to violence in opposing the Franco government, which suppressed opponents and banned minority cultures and languages, including that spoken by the Basques. The group’s methods at first drew support from a wide range of Franco’s opponents.
But it continued to rely on terrorism even after Franco had died, Spain had returned to democracy, and the central government had granted significant autonomy to the Basque region and others.
ETA’s use of violence backfired, ensuring now that “the Basque secessionist project will not make any substantial progress until the legacy of deaths and economic losses becomes a distant memory,” said Diego Muro, a Spanish lecturer in international relations at the Handa Center for the Study of Terrorism and Political Violence at the University of St Andrews, in Scotland.
He said the group’s dissolution “brings to an end the ethnonationalist wave of terrorism that started with the anti-colonialist violence of the second half of the 20th century.”
In its letter, ETA wrote that a “lack of will to solve the conflict” had prolonged it, and “multiplied the suffering,” and acknowledged that the group was at least partly to blame.
“ETA recognizes the suffering caused as a result of their struggle,” it added.
In June 1968, two ETA militants killed a policeman who had stopped them to check their papers and inspect their car — the first death attributed to the group. Two months later, it carried out its first planned assassination, ambushing a police inspector, Melitón Manzanas — who was suspected of torturing communists who resisted Franco — outside his home in Irún, on the French border.
In 1973, ETA struck at the top of Franco’s government, killing the prime minister, Adm. Luis Carrero Blanco, with a bomb so powerful that the explosion sent his armored limousine flying over a building. The assassination left Franco, who had only two years to live, without an obvious successor.
As Spain transitioned to democracy after Franco’s death, a law enacted in 1977 granted amnesty for crimes committed during the civil war of the 1930s and Franco’s subsequent dictatorship. Spain also began a process of political decentralization that gave regions their own parliaments and significant powers over areas like education and health. The Basque region and a neighbor, Navarre, also received the important right to collect taxes.
But ETA rejected such political concessions and instead stepped up its terror campaign demanding an independent state it called Euskal Herria. The group envisioned a nation that would stretch far beyond the modern borders of Spain’s Basque region, to include Navarre and the Basque region of southwest France.
In 1980, its bloodiest year, ETA killed almost 100 people, in attacks that increasingly claimed civilian victims. In 1987, in its worst single attack, an ETA bomb killed 21 people at a Barcelona supermarket.
By then, each attack provoked a national outcry. In July 1997, six million people took to the streets to protest the assassination of Miguel Ángel Blanco, a local conservative politician, who was kidnapped and killed by ETA.
Starting in the late 1980s, ETA announced several cease-fires and occasionally held talks with the Spanish government, first under the conservative prime minister José María Aznar, and then under the Socialist administration led by José Luis Rodríguez Zapatero. But the negotiations and cease-fires repeatedly broke down, while the Spanish government continued to ban politicians seen as being linked to ETA from running in elections.
Then, after the arrests of many ETA leaders and operatives, the violence stopped. ETA last killed someone on Spanish soil in 2009, and its last victim anywhere was a French policeman, shot in 2010 during a botched car theft near Paris.
The group announced another cease-fire in October 2011, and this one held. Last year, it offered to disarm itself, and disclosed the locations of some of its weapons caches.
Even as the government dealt with the emergency of another secessionist movement, this one in Catalonia, the Spanish authorities, working in close cooperation with French and other police forces, continued to arrest ETA members and seize hidden weapons. Security experts say the group has been so depleted that it can no longer carry out operations.
Since the 2011 cease-fire, the conservative government has rejected international mediation efforts, determined not to allow ETA a brokered deal like the one that ended hostilities in Northern Ireland between the British government and the Irish Republican Army. The Spanish government fears that ETA members and sympathizers could score political points with a negotiated surrender.
Last month, Spain’s interior minister, Juan Ignacio Zoido, warned that ETA would not win any concessions in return for dissolving itself. One of the outstanding issues is whether the government will transfer imprisoned ETA members, who are scattered across the rest of Spain, to prisons in the Basque region.
ETA “didn’t get anything for stopping to kill and will not get anything for declaring its disappearance,” Mr. Zoido said.
Alfonso Alonso, the leader of Spain’s governing Popular Party in the Basque region, also poured cold water on the significance of ETA’s plan to dissolve itself.
“Neither its history nor its responsibility can be dissolved,” Mr. Alonso said recently. “We will never forgive ETA.”