A Spanish far-right party doubled its standing in a national election Sunday that made clear just how polarized Spanish politics has become and did little to help end the government’s long deadlock.
The results were a setback for Pedro Sánchez, the caretaker Socialist prime minister, who had hoped the election might strengthen his hand as he tries to form a new government.
The election — the fourth in four years — came after months of fruitless coalition talks between Mr. Sánchez’s party and a smaller left-wing party, Unidas Podemos.
Though Mr. Sánchez’s Socialists came out on top again, they won only 120 of the 350 seats in Parliament — three fewer seats than in April, when the last election was held.
The biggest gains Sunday were made by the ultranationalist and anti-migration Vox party. It is now Spain’s third-largest party after doubling its seats to 52 from 24, according to preliminary results, with more than 99 percent of the votes counted.
With the rise of a powerful far-right party, Spain now mirrors other countries in Europe.
“We used to talk about Spain being the European exception, but that is now clearly gone,” said Astrid Barrio, a professor of politics at the University of Valencia.
Spanish politics, she said, long defined by a left-right and two-party split, was now “very clearly shaped by the ideology of nationalism, with Vox as the clearest answer to the Catalans.”
Sunday’s election confirmed the impact of the Catalan secessionist conflict on national politics, particularly after tensions recently spilled over into violence on the streets of Barcelona and other Catalan cities.
Speaking in Madrid after the polls closed, a triumphant Santiago Abascal, the leader of Vox, thanked more than three million voters for choosing the “patriotic alternative” offered by his party.
And he told supporters that Vox would “not take a step back” in pushing for a program that includes stripping the regions of Spain of their administrative autonomy.
“We have managed to open up all the prohibited debates,” he said.
Earlier this month, Mr. Abascal used his first election television debate to demand the banning of separatist parties as “criminal organizations.” He called for another period of direct rule over Catalonia by Madrid, tougher than the one imposed in late 2017 after separatist leaders made a failed attempt to declare independence.
Mr. Abascal also peppered his remarks with xenophobic comments about migrants and Islam. His party has called for building walls around two Spanish enclaves in Africa, to stop migrants from entering illegally.
Mr. Sánchez could still form a new government if he manages to get the support of not only Unidas Podemos but also other smaller parties, including Basque and Catalan ones.
Help might come from the anti-secessionist Ciudadanos party. It has long been opposed to Mr. Sánchez, but its disastrous showing on Sunday, when its representation fell to 10 seats from 57, might lead to a change in party leadership.
Addressing his supporters from the balcony of his party headquarters just before midnight, Mr. Sánchez celebrated his party’s victory, however diminished, and promised to form a new government. He called on his rivals to show “generosity and responsibility” to help end the deadlock, but offered no indication of exactly how he might win them over in a new round of negotiations.
Other parties did not seem well disposed to the prime minister.
Pablo Iglesias, leader of Unidas Podemos, accused him of “leaving us with one of the strongest far-right parties in Europe.” And Íñigo Errejón, leader of another small left-wing party, said the rise of Vox was “the symptom of a democratic attrition and the result of a historic responsibility” — Mr. Sánchez’s decision to risk another election rather than forming a left-wing coalition.
In April, when Mr. Sánchez mobilized left-wing voters to stop Vox’s rise, he was greeted with a near-record turnout of 76 percent. On Sunday, the turnout fell to 70 percent, reflecting frustration among voters about their party leaders’ inability to form a government, let alone resolve the lengthy conflict in Catalonia.
The main opposition, the conservative Popular Party, won 87 seats, up from 66 in April, which was its worst-ever result. Its leader, Pablo Casado poured cold water on Mr. Sánchez’s chances of forming a new government.
“Why did he want to convene another election if it was meant to create more stability, when now he has it much harder to form a government?” Mr. Casado asked. “Spain cannot remain in a blockade much longer.”
Last month’s prison sentencing of former separatist leaders set off an outburst of street violence in Catalonia that raised concerns over whether the long-simmering conflict was spinning out of control. That led right-wing parties to put pressure on Mr. Sánchez to use the executive’s emergency powers to restore law and order in Catalonia.
Catalan society remains split down the middle by secessionism, with three separatist parties winning on Sunday a combined 23 of the 48 Catalan seats in the Spanish Parliament.
Four years ago, Spain’s two-party system turned into a much more fragmented landscape, and since then no single party has come close to winning a parliamentary majority. Spain spent most of 2016 in political limbo, after two elections failed to break the deadlock, and has found itself facing a similar scenario this year.
The repeat election on Sunday, and its result, confirmed “the irresponsibility and short-term strategies of the party leaders,” said Ms. Barrio, the politics professor.