By Danny Wood
BBC News, Madrid
Spaniards have been in this situation before.
The airport bombing has left Spain disappointed, not shocked
So there is little surprise that after nine months of its so called "permanent ceasefire" Eta has returned to bomb attacks.
But there is certainly disappointment. The majority of Spaniards were in favour of their prime minister's attempt to solve the Basque conflict through dialogue.
Even though Batasuna, the illegal Basque political group regarded as a mouthpiece for Eta, has denied that the ceasefire is over, the proof for most Spaniards is in the bombing.
Spaniards will be angry and disappointed that once again, Eta has demonstrated an unwillingness to stop its attacks - as promised in the so called permanent ceasefire - and that Batasuna has demonstrated a similar reluctance to condemn these violent acts.
During the 1980s a number of temporary ceasefires were announced, some with a 60-day limit.
In 1998 the armed separatists announced an "indefinite and unilateral" truce which led to talks with the conservative government of Jose Maria Aznar. Those meetings failed and bomb attacks resumed.
The condition for this latest process of dialogue between the government and Eta - an absence of violence - was approved by Spain's parliament - in the face of strong opposition from the conservative Popular Party.
There have been sporadic outbreaks of street violence in the Basque region since the latest ceasefire, announced in March 2006, which have increased the political pressure on the government.
But this bomb attack at Madrid's International Airport is a very clear violation of the ground rules set by Spain's parliament.
Which is why the Spanish government has been emphatic about the state of play with this peace process. The Minister for the Interior, Alfredo Perez Rubalcaba, says Eta has broken, liquidated and finished off the peace process.
But it looks as if Prime Minister Jose Luis Rodriguez Zapatero was initially very reluctant to put a final end to this peace initiative.
Hours after the bombing the prime minister announced the "suspension" of dialogue with Eta rather than an end to the peace process.
It is possible the government was hoping for an emphatic signal from Batasuna, the illegal Basque party regarded as the mouthpiece for Eta, condemning the attack and renouncing violence.
That might have made a resuscitation of this process a possibility.
But that renunciation of violence from Batasuna has not been forthcoming. In declarations after the bomb attack, Batasuna has said Eta should explain the reasons for its attack and blamed the government for the current situation.
Zapatero initially seemed reluctant to end the peace initiative
Eta and Batasuna have not been happy with the peace process for some months.
In several recent declarations they made it clear they believed the process was in crisis. They want the government to re-legalise Batasuna and stop prosecuting Eta suspects - including those accused of murdering innocent civilians.
The government has refused and wants Batasuna to renounce the use of violence if it wants to take part in the political process.
Josu Jon Imaz, the leader of the moderate Basque nationalist party that governs the Basque region, says that the bases for sustaining the current peace process do not exist and has strongly criticised what he describes as the servile attitude of Batasuna and its inability to condemn violence and behave like a real political party.
This impasse between Spain's political parties and the illegal organisation Batasuna helps to explain why after nine months of ceasefire, officially, there have been no meetings between the national government with either Batasuna or Eta.
At the moment the current peace process is over.
But the Spanish government has not given up hope. It is due to start a round of meetings with the main political parties to try and come with another strategy to deal with separatist conflict in the Basque region.