Spain holds its third general election in four years on Sunday, in a battle between the established parties, Catalan and Basque nationalists, and a rising far right.
This time, however, the electoral game has changed.
Support for the previous winner, the conservative Popular Party (PP), has collapsed amid a corruption scandal. Its main opponent, the Socialist party, has climbed to the top of the polls after taking over the prime minister's job last year.
Podemos on the left and Ciudadanos (Citizens) on the right are seeing their support fall, amid a boom for the controversial far-right Vox party.
The last pre-election polls suggested that up to four in 10 voters had yet to make up their minds.
What are the possible outcomes?
Opinion polls may not tell the full story, particularly with so many undecided voters. But potential outcomes for a government include:
- Socialists, left-wing Podemos, plus small nationalist parties
- Centre-right PP, liberal Ciudadanos and far-right Vox
- Socialists and Ciudadanos
But there is a problem with each of these combinations.
The Socialist and Podemos alliance of Prime Minister Pedro Sánchez's existing government needed the Basque and Catalan nationalists to support it. In the national televised debates ahead of polling day, his alliance with Catalan nationalists was used as a key weapon against him - with his opponents claiming he was linked to "enemies of Spain" and wanted to "liquidate" the country.
The Catalan pro-independence parties were partly responsible for the government's collapse when they pulled their support in February; and the crisis over the failed Catalan independence bid has made the separatists hugely unpopular in much of Spain - making negotiations with them tricky.
Any Popular Party coalition with Ciudadanos would probably need the support of Vox.
As the campaign came to a close, PP leader Pablo Casado appeared to open the door to a coalition with Vox. If between them they had enough seats, why would they want to block a coalition, he said, aware that many former PP voters planned to switch to Vox.
But Ciudadanos voters are largely opposed to entering government with Vox. Vox was prevented from taking part in the debates by the country's electoral commission.
Ciudadanos has also publicly said it will not form a coalition with the Socialists, and leader Albert Rivera has bitterly criticised the Socialist leader over Catalonia. During the election debates, Mr Sánchez said he had no plans to join with a party that had placed a "cordon sanitaire" around the Socialists.
What are the issues?
The Catalan crisis and the rise of Vox have changed the debate in Spanish politics.
"This is not an election about the economy - a different situation from what we have seen in more than 20 years," says Juan Rodríguez Teruel, professor of political science at the University of Valencia.
Despite widespread concerns about unemployment - which remains high in Spain compared with its European neighbours - it barely featured during the campaign and was raised during the debates only briefly.
"The campaign is going to remain around identity issues, and particularly around the Catalan issue... it seems that the economy is not, any more, the completely fundamental issue," says Prof Teruel.
Before the election, Mr Sánchez had been negotiating with Catalan parties to support his budget. But those talks broke down amid a public backlash over the meeting, partly stoked by Vox's fervent opposition to any concessions on independence.
Despite his political problems, support for the Socialists has risen during their time in government - at the expense of coalition partner Podemos.
Meanwhile, support for its tradition rival, the PP, plummeted in the wake of the corruption scandal that brought down previous leader Mariano Rajoy - leaving plenty of votes to fight for among a fragmented right.
Why is Vox doing well?
The nationalist party has set itself up in firm opposition to the separatists, despite Spain's dark history with the far right under dictator Francisco Franco.
"The rise of Vox is clearly an earthquake in Spanish politics," says Bonnie N Field, professor of political science at Bentley University - while warning against "exaggerating" the party's success.
Opinion polls suggest it has around 11% support, while its leader Santiago Abascal has the lowest opinion rating of any party leader.
Nonetheless, she says "Spain has gone from what political scientists Sonia Alonso and Cristóbal Rovira called 'no country for the populist radical right' to one where the far right could support – or less likely, join – a right-wing government".
Such an arrangement is precisely what happened in the regional government of Andalusia - where the PP, Ciudadanos, and Vox formed a right-wing regional government earlier this year for the first time in 36 years.
"If the right is in reach of a majority after the general elections, something similar may occur," Prof Field says.
For Prof Manuel Arias Maldonado of the university of Malaga, Vox's success is partly down to its awareness of history, and "adopting a low profile".
"It should be noted that they do not display openly any Francoist imagery," he said. "They are not making gross mistakes."
"The big question [about the elections] is how strong will Vox be. There is the feeling that they could surpass expectations, despite the polls.
"But the main reason why Vox exists is Catalonia: it is a reaction to the unilateral secession attempt... that is where their strength comes from."
Could the right really win?
A three-party coalition of the right is not out of the question.
But Prof Teruel warns that the surge for Vox is coming at the expense of other right-leaning parties - the PP or Ciudadanos. And for the first time since the 1970s, the right is "very fragmented" - something that could benefit opponents on the left.
"The main reason now to vote for the left-wing electorate is to avoid the potential coalition among right-wing parties," Prof Teruel says.
Ciudadanos, meanwhile, could feasibly support a coalition with the Socialists, despite publicly dismissing the idea.
"I'm not sure they could keep this position if the numbers give the potential of a coalition," Prof Teruel says.
"The pressure on Ciudadanos will be very, very high."
Spain's El País newspaper, publishing its final analysis of all the polls before the vote, concluded that the chances of a three-party right-leaning government was about 10%; far lower than any combination involving the Socialists.