The radical movement of Basque separatists was organized in 1959 when the group known as Basque Fatherland and Freedom (Euskadi Ta Askatasuna--ETA) broke away from the much larger Basque Nationalist Party (Partido Nacionalista Vasco--PNV). The ETA adopted a policy of armed struggle in 1968; in practice, much of the violence was attributed to an extremist faction, the ETA Military Front (ETA Militar--ETA-M). A less violent faction, the ETA Political-Military Front (ETA Politico-Militar--ETA-PM), pursued a strategy of mixing political activities with terrorist actions. The ETA-M was largely responsible for the mounting savagery of the attacks during the 1970s, which included the assassination of the prime minister, Admiral Luis Carrero Blanco, in 1973.

The election of a democratic national parliament in 1977 and a Basque parliament in 1980 brought little relief from ETA violence. Although avowedly socialist in orientation, ETA continued to justify its terrorist policies after the Socialist government came to power in 1982. It insisted that the PSOE was only a pawn of the capitalist and clerical forces that dominated Spain and that it had failed to offer real autonomy to the Basque people.

The ETA-M was considered to be the militant wing of Popular Unity (Herri Batasuna--HB), the most radical of three Basque parties represented in the Cortes. Although the HB increased its representation in the Cortes to five seats in 1986, it still received only 17 percent of the Basque vote. The party's platform included the compulsory teaching of the Basque language, Euskera, in the schools; the withdrawal of Spanish security forces from Basque territory; measures to restrict private capital; and the addition of Navarre to the three provinces of the north that constituted the existing autonomous community of the Basque Country. As its ultimate objective, the party favored complete independence from Spain.

ETA-M's strategy had been to carry out a series of carefully selected assassinations and bombings, each having important psychological or symbolic impact. The terrorists thus hoped to inspire a spiral of violence and counterviolence that would arouse feeling against "repression" by the security forces and that would perhaps provoke a right-wing coup by the armed services. A total of more than 700 deaths had been attributed to the movement by the close of 1987. The violence had reached its peak in 1980 when the death toll was eighty-five. Nearly two-thirds of those killed were members of the Civil Guard or the National Police Corps. Most of the remainder were civilians killed in bombings or caught in crossfire. The military represented only 7 percent of the deaths, but those selected for assassination were often senior officers holding prominent positions.

The activists of ETA-M, believed to number no more than 200 to 500 in 1986, were organized into cells of as few as 5 individuals. Most members were under thirty years of age, and they had served for an average of three years in this sideline to their ordinary jobs. Perhaps no more than 100 were actual gunmen, the others acting as messengers, transporting weapons and explosives, and providing support. A number of young women also served in ETA-M; they were said to be among the most uncompromising militants, willing to take risks that young men increasingly shunned.

By the mid-1980s, ETA-M appeared to be under growing pressure from the security forces, with the result that the incidence of terrorist acts had tapered off. Better use of informants, ambushes, raids, and tighter control of the border with France contributed to the success of the police efforts. In 1984 the Spanish government had announced a policy of "social integration," a form of amnesty offered to ETA members in exile or in Spanish jails if they renounced future acts of terrorism. Improved international cooperation was also important. In 1986 about 200 active terrorists were believed to be living among the large Basque population in the adjacent provinces of France, using French territory as sanctuary and as a base for terrorist missions. Two years later, their numbers had been reduced to a few dozen as a result of intensified cooperation between Spanish and French security authorities. Until 1983 France, citing its tradition of granting political asylum, had been unwilling to extradite ETA members to Spain. France shifted to a more accommodating policy, after the new Socialist government took office in Spain, and permited the extradition of a few ETA members, accused of specific crimes of violence, while resettling others in northern France or deporting them. In late 1987, the police claimed a crippling blow had been administered to the terrorists by the arrest of many senior members of ETA-M in both Spain and France and the discovery of caches of arms and explosives.

Sympathy among Basques for the extremists, which was already limited, diminished further following the bombing in 1987 of a supermarket garage in Barcelona, in which twenty-four innocent people were killed. Later in the same year there was popular revulsion over the deaths of five children among eleven people killed in a bombing of family quarters of the Civil Guard at Zaragoza.

Beginning in late 1983... an offshoot of ETA-M, Spain Commando, targeted members of the Civil Guard and the armed forces in Madrid, where such attacks, which gained maximum publicity for the movement, had been on the rise.

ETA-M was at one time well financed by kidnappings, robberies, and the so-called "revolutionary tax" on Basque businessmen. Reportedly, however, after the reverses suffered by the terrorists in 1987, receipts from the tax had declined almost to zero.

The regional Basque police force, Ertzaintza, formed in 1981, originally was assigned to traffic and other nonsecurity duties, but in late 1986 it conducted its first engagement against ETA-M. A plan had been adopted for Ertzaintza gradually to take a larger role, but it was reported that Civil Guard officers were reluctant to turn over intelligence out of conviction that the autonomous police were infiltrated by ETA activists.