Spain goes to the polls Sunday for its third general election in four years, as socialist Prime Minister Pedro Sánchez tries to break the political deadlock that has gripped his country and left him unable to govern.
Over the last five years, the rise of new political forces – including the far-right – and a constitutional crisis over Catalan leaders ' attempt to secede unilaterally from Spain, have transformed the political landscape, upending the two-party system in which the leftwing Socialist Workers Party (PSOE) and rightwing Popular Party (PP) have ruled since the 1980s . With some 30% of voters still undecided, Spain's political future has rarely been so uncertain.

This time, however, the electoral game has changed.

Support for the previous winner, the conservative People's 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.

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.

BBC