ETA'S car-bomb on Monday night nearly caused a small massacre in the Basque city of San Sebastian.
Fortunately, none of the seven victims was killed. But the attack, the third since ETA ended its ceasefire, abruptly hijacked front pages and dictated changes in the agenda of party rallies, as the race towards next Sunday's general election enters its final stretch.
This week's litany of condemnation and recrimination is sadly familiar. The underlying reality is that the bombing has increased the chances of a first absolute majority for Mr Jose Maria Aznar's centre-right Partido Popular (PP). ETA's return to terrorism means that some floating voters may feel safer with the known quantity of Mr Aznar's outgoing administration than with the only likely alternative, a left alliance led by the Socialist Party (PSOE).
The PSOE is led by the untried and uncharismatic Mr Joaquin Almunia. No one is quite sure how the very recent and rather shaky pact between the PSOE and the Communist-led United Left (IU) would work in practice.
The PSOE could never be accused of being "soft on terrorism". But IU used to participate in a Basque platform which included ETA's political wing. The PP is not slow to remind voters about this.
Mr Aznar has also accused the PSOE of secretly courting moderate Basque Nationalist Party (PNV) support, without demanding that the PNV should first totally ostracise ETA's political wing.
Mr Aznar might have won an absolute majority without this late surge of support. There is a well-sourced rumour that the PP suppressed an opinion poll a week ago which shows them outvoting the entire opposition. The PP, of course, denies this.
All published polls to date show Mr Aznar's party to be about five points ahead of the PSOE, not enough to govern without support from the Catalan nationalists. The PP depended on the Catalans in the last legislature, and would dearly love to be shot of them. Their backing does not come cheap, in either political or economic terms.
Why then, might Mr Aznar hide from the public the good news that one poll shows him winning solo? The reason would be fear of complacency. If you tell your voters you have it in the bag, the argument runs, they won't bother to turn out.
Apathy is certainly the curse of all the campaigns. For the last few days, the PP has bravely mounted a little stand in the Puerta del Sol, one of Madrid's most popular plazas.
It is also the site of a mentidero, the place where returned travellers used to address the credulous populace and, according to the tradition which gives the mentidero its name, tell them a pack of lies.
The PP has no such base intentions, perish the thought. But its militants have difficulty finding any audience at all. Thousands of people stroll past hourly, at the gentle pace of Madrid's spring paseo, but hardly anyone stops.
An immaculately coiffed senora of a certain age, dressed in blue from neck to toe, seemed to lose the plot when she declared that her party "could solve all the country's problems in the next four years". No one bothered to either applaud or contradict her.
The PSOE suffers from a similar lethargy. A meeting in Madrid to discuss the party's cultural policy attracted less than 100 supporters.
Most of them seemed to be friends of the people on the platform, all of whom were men, and none of whom will see 50 again. They indulged in an orgy of nostalgia for their gilded youth as anti-Franco revolutionaries, which has very little relevance to the policies the Socialists actually pursued in power under Mr Felipe Gonzalez.
The issue which has generated most heat throughout the campaign is pensions. Six years ago, all parties agreed that the pension system was in such serious crisis that its protection should be above party politics. But more than a third of the electorate are pensioners.
Mr Aznar claims that his government's economic success permits him to offer them a surprising range of increases. The Socialists have been slightly more cautious, but are also involved in an "auction of promises", which has earned them criticism from their allies in the United Left.
As the campaign moves towards its finale, the only move which seems capable of upsetting Mr Aznar's march to at least partial victory is an extension of the terms of the left alliance.
If IU were to withdraw its candidates in areas where it stands no chance of winning, the PSOE could take crucial extra seats. But the party is leaving it to the last minute to declare its hand.