A convincing victory for the Socialist party (PSOE) in Spain’s general election on Sunday has dealt a blow to the prospect of a rightwing coalition with the far-right Vox. The verdict is a personal triumph for Prime Minister Pedro Sánchez, who failed to save his minority government in February despite having regained the party leadership. The PSOE is short of the 176 required for a governing majority. Yet, it is in some ways spoilt for choice: it can either enter into a formal alliance or rule on its own. Mr. Sánchez can count on issue-based support. Encouragingly, the anti-capitalist Podemos has indicated a readiness to work in a PSOE-led coalition. It had nurtured ambitions of overtaking the PSOE as the principal force on the political left after the 2015 elections, but now its current stance stems from what it sees as a larger role to isolate the conservatives and the far-right. The chances of the liberal Ciudadanos supporting the PSOE are remote, as the former seems set on replacing the conservative Popular Party as Spain’s main centre-right alternative. In any case, Ciudadanos’s more recent proclivity to cohabit in a coalition with theVox may not go down well with the PSOE rank and file. Collaboration with the Catalan secessionists would be equally hard. They had in February joined the Opposition to vote out Mr. Sánchez’s government, which insisted on negotiating a settlement within the framework of the Constitution. One of the parties has demanded a second Catalan referendum and the withdrawal of the sedition trial against separatist leaders as a condition for supporting Mr. Sánchez again.
The victory in Spain is the latest in a string of successes for social democrats in the European Union, since the xenophobic backlash in many countries after Germany welcomed about a million Syrian refugees in 2015. Yet, the unfolding political fragmentation and the erosion of two-party dominance across Europe also means these gains cannot be exaggerated. As voters in the 28-nation bloc brace themselves to elect a parliament this month, this new reality could become more manifest. Halting the populist surge — as exemplified in Britain’s vote to leave the EU — opposed to freedom of movement and closer European integration is their biggest challenge. Centrist forces have responded to the extremist threat by leaning either too much to the left or to the right, hollowing out the middle ground. Such pandering to populists has cost them dearly. It is time moderate parties abandoned this perilous course. The near-unambiguity of Mr. Sánchez’s latest mandate is the envy of most governments around Europe. Having been handed one, he must ensure a full term in office, something that has eluded Spain for some years.