By Dominic Bailey
BBC News Online, Madrid
Spain is going to the polls under a dark cloud.
All the conventional issues have been overshadowed
The new chapter that general elections are supposed to bring came three days early with the bomb attacks on commuter trains in Madrid.
Elections or no elections, the future will always be post-11 March not post-14 March.
One of the country's leading dailies, El Pais, summed up the mood when it said: "It is inevitable that the elections will take into account the situation created by the attacks".
Spaniards are grieving, still recoiling from stunned disbelief, but they are also angry.
At the peace demonstrations on Friday , millions across Spain directed that anger at the bombers who left 200 dead and more than 1,000 injured.
The protest was a symbol that they would not be broken by terror.
Turn-out for the polls - which was 68% in 2000 - is expected to be higher this year as voters reinforce that message that bombs cannot break their democracy.
But the governing Popular Party (PP), which had been widely expected to win, has also been a target for that anger and frustration.
The interior minister promised total transparency in the investigation
At the peace marches and at "spontaneous" protests outside PP headquarters in Madrid on Saturday, thousands demanded "Who was it? Tell us the truth" and held up banners warning "Don't play with the dead".
El Pais referred to "the more than dubious attitude of the government in relation to the lines of investigation".
And protesters accused the government of managing the release of information about the attacks to their own political ends.
Until the arrests on Saturday, the government had insisted its prime line of investigation was directed at the Basque separatists Eta, although the scale of the attack and devastation it caused left some unconvinced.
If Eta is to blame it would justify the PP's hard line against the group and separatism in Spain.
But if al-Qaeda is to blame, however, it would bring into question Spain's decision to join the United States and Britain in the war on Iraq, something 90% of Spaniards opposed.
The newspapers have different views of the government's behaviour over the last few days.
ABC says that "in little more than 48 hours the Interior Ministry has been able to present citizens the first concrete results of the police investigation into the 11-M attacks... The Executive and Jose Maria Aznar have behaved with efficiency and transparency."
But El Mundo calls the latest arrests "an embarrassing situation for the government just a few hours from the elections".
Some are sceptical about the ruling party's response
La Razon noted that "it would have been better to know these facts (about the arrests) on Thursday so that the election campaign wouldn't suffered such uncertainty. But what is certain is that seldom has a police force showed the efficiency of the Spanish police."
Electrician Karim Al-Jadyan, 33, believes the bombing will affect the outcome of the elections, but could not predict whether PP would be defeated or gain a majority.
"I think there will be changes," he said. "When something like this happens there is a change for something new. There will be a new way of thinking, new laws for everything and no more flexibility."
Felipe Clavello, 72, and his wife Carmen, 72, said people were disappointed with the government but they preferred Jose Maria Aznar's successor Mariano Rajoy to the Socialist (PSOE) leader Jose Luis Rodriguez Zapatero, the main challenger.
As people go to cast their votes, party political posters put up before 11 March are now side-by-side with black ribbons of mourning.
How much change Spain wants will be decided by Monday morning.