A strong showing Sunday by a pair of upstart parties in Spain's general election upended the country's traditional two-party system, with the ruling Popular Party winning the most votes but falling far short of a parliamentary majority and at risk of being booted from power. Days or weeks of negotiations may be needed to determine who will govern Spain, with the new far-left Podemos and business-friendly Ciudadanos parties producing shockwaves because of strong support from voters weary of high unemployment, a seemingly endless string of official corruption cases, and disgust over the country's political status quo.
If forced out of government, Prime Minister Mariano Rajoy and his Popular Party would become the third European victims this year of a voter backlash against austerity—following elections in Greece and Portugal seen as ballot box rebellions against unpopular tax hikes and spending cuts invoked during the eurozone's debt crisis. In past Spanish elections, the Popular Party and the main opposition Socialists were the established powerhouses and only needed support from tiny parties to get a majority in parliament when they didn't win one from voters. But Podemos came in a strong third place and Ciudadanos took fourth in their first election fielding national candidates—setting up a period of uncertainty as parties negotiate with each other to see which ones may be able to form a governing alliance. (Read more about Spain's general election.)