The Spanish government has accused the Basque terrorist group ETA of responsibility for back-to-back bombings last week that killed two people and injured more than 50 others. The bloody attacks came as ETA – short for Euskadi Ta Askatasuna, or Basque Fatherland and Freedom – marked the 50th anniversary of its founding. Analysts say ETA, which has been considerably weakened in recent years by aggressive counterterrorist police sweeps in Spain and France, hopes the bombings will not only boost sinking morale among its followers, but also force the Spanish government back to the negotiating table.
 
The latest attack, which killed two Guardia Civil police officers on Thursday, occurred on the Spanish holiday island of Mallorca. Security forces say ETA operatives booby-trapped the victims' police car outside their barracks with a remote-controlled bomb. Police later deactivated another bomb placed beneath a second car near the site of the first explosion. Authorities briefly closed all ports and airports on the island in an effort to prevent the bombers from escaping.
 
The Mallorca attack came just one day after a pre-dawn bomb targeted the family quarters of Civil Guard officers in the northern Spanish city of Burgos, injuring 66 people, including sleeping children. The force of the explosion left a deep crater outside the barracks and blew off much of the façade of the 14-story building. The government said ETA had been hoping to cause a massacre, but encountered problems parking the bomb-laden vehicle.
 
Observers say ETA is under pressure to show it can still mount attacks despite having been weakened by a series of high-profile arrests. These include the detention of ETA's top military commander, Jurdan Martitegi, in April, the third top ETA military chief to have been arrested since November 2008. Police also captured the head of ETA's logistics apparatus in September 2007, as well as the head of its political apparatus in May 2008. Nearly 20 other suspected lower-level ETA members were arrested during a three-week period in June and July 2009.
 
ETA was founded on July 31, 1959, when a group of dissident student radicals broke away from the Basque Nationalist Party (PNV) and formally announced their drive for Basque secession. The group was quick to embrace violence: ETA's first victim was 22-month-old María Begoña Urroz, who was killed in June 1960 by a bomb at a train station in the Basque town of San Sebastián. Since then, ETA has killed nearly 900 people in its drive for Basque independence.
 
One of ETA's most notorious attacks was the December 1973 assassination of Spanish Prime Minister Luis Carrero Blanco, at the time considered a favorite and likely successor of Spain's dictator, Gen. Francisco Franco. Carrero Blanco was killed when an explosion catapulted his car into the air and over the roof of a Madrid church where he had just attended mass. The vehicle landed on the second-floor balcony of a building on the other side of the church.
 
The decade of the 1980s marked the peak of Basque violence. ETA's bloodiest year was 1980, when it killed 91 people, nearly half of whom were civilians. ETA's single deadliest attack was in June 1987, when a car bomb in the parking lot of a supermarket in Barcelona killed 21 people and wounded 45. By comparison, during the first half of 2009, ETA attacked nine times, killing three people.
 
In 1992, the year in which Spain hosted the Olympic Games in Barcelona and the Universal Expo in Seville, ETA vowed an unprecedented bombing campaign to bring the Spanish government to its knees. But in March of that year, Spanish and French police outmanoeuvred the group by arresting its entire senior leadership during a raid on a chalet in the French town of Bidart. It was a blow from which ETA never fully recovered.
 
In April 1995, an ETA car bomb failed to kill José María Aznar, the conservative opposition leader and future prime minister. During his subsequent time in office from 1996 to 2004, Aznar implemented a counterterrorism policy widely credited with having essentially eradicated ETA.
 
Believing it might have more success engaging Aznar's successor, Socialist Prime Minister José Luis Rodríguez Zapatero, ETA in 2006 announced a "permanent ceasefire." In a statement released to Basque media, the group said its new objective was "to promote a democratic process in the Basque country."
 
In what turned out to be a major miscalculation, however, Zapatero refused to demand that ETA first lay down its weapons as a precondition to peace talks. Instead, he pulled out of an agreement with the opposition Popular Party that he himself had proposed in 2000, which stipulated that there would be no talks with ETA unless the group agreed to disarm. The subsequent split between Spain's two main political parties limited public support for a negotiated settlement, leaving Zapatero unable to meet any of ETA's demands. With the peace talks quickly arriving at an impasse, ETA reverted to violence soon thereafter, breaking its ceasefire with the Madrid airport bombing in December 2006.
 
Since then, the Spanish and French authorities have launched an unprecedented crackdown on the group. Nearly 100 ETA suspects have been arrested in Spain and France since the Madrid bombing alone. And there are now some 700 ETA convicts or suspects in Spanish jails, with another 150 imprisoned in France.
 
Meanwhile, ETA has also been weakened by an internal power struggle between hardliners who want to continue the campaign of violence and those who want a political solution.
 
Although last week's attacks have proven that ETA is still able to kill, relentless counterterrorism pressure has more often than not resulted in arrests of the group's commandos before they can attack. Moreover, ETA's military chiefs now manage to last mere months, as opposed to years, before they are captured. As Spanish Interior Minister Alfredo Pérez Rubalcaba said, "ETA can still do us a lot of harm, but to join the group now is to buy a ticket that leads directly to prison."
 
This article was published by World Politics Review on August 1, 2009.

Soeren Kern is Senior Fellow for Transatlantic Relations at the Madrid-based Grupo de Estudios Estratégicos / Strategic Studies Group.