Brazilian voters on Sunday handed the leftist president, Luiz Inácio Lula da Silva, a fourth term in office and a surprise victory over Flávio Bolsonaro, his right-wing challenger, in a striking rebuke to a conservative surge sweeping Latin America.
Mr. Bolsonaro refused to accept the outcome and said it was the result of foul play, increasing the risk of unrest over the election result.
The rejection by voters of Mr. Bolsonaro, the son of a former president jailed for attempting a coup four years ago, is also a loss for President Trump, who had embraced the Bolsonaro family and the region’s rising right.
Mr. Lula, in contrast to many world leaders, has often and defiantly clashed with Mr. Trump, and his victory highlights that Latin America’s left-wing forces still wield influence despite a string of losses across the hemisphere. This is the first leftist victory following seven straight wins by right-wing leaders in the region over the last 18 months.
“I would like to thank the Brazilian people for the generosity they have shown me for a long time,” Mr. Lula said, during a victory speech in São Paulo, flanked by his wife, running mate and allies.
The result capped a chaotic final stretch of the race, as polling places were ordered to remain open after public transportation delays and torrential rains disrupted voting. The extended polling hours, which both candidates asked for but came right as voting was set to conclude, opened up the possibility that the results would be disputed.
Mr. Bolsonaro called an order by Brazil’s judiciary to extend voting a “dirty trick” and demanded the election be annulled.
“There’s a lot that needs to be cleared up before Brazil simply accepts this foul play that took place in these elections,” he said during a news conference in Brasília, the capital.
Mr. Bolsonaro’s party will now likely petition electoral authorities for a review of the result.
Since Brazil’s return to democracy, no presidential election has ever been annulled. In 2014, the losing party requested an audit, but that review found no evidence of fraud and the results were upheld.
In 2022, Mr. Bolsonaro’s Liberal Party similarly challenged his father’s loss in the election, but the court ultimately fined the party more than $4 million for failing to provide evidence to support its allegations.
Among Mr. Bolsonaro’s supporters on Sunday, the sentiment was one of sadness and indignation. “We know we’ve been robbed again,” said Valéria Maria de Melo, a 49-year-old housewife, bursting into tears.
Mr. Lula headed into Sunday’s vote as the underdog after finishing 2 percentage points behind his opponent in the first round of voting earlier this month.
But on Sunday, Mr. Lula achieved a stunning comeback, winning 51.8 percent of the vote versus 48.2 percent for Flávio Bolsonaro, with nearly all the ballots counted.
Mr. Lula’s margin of victory on Sunday was roughly double the margin four years ago when he narrowly defeated Mr. Bolsonaro’s father. It was the first time in Brazil’s history that a candidate who lost the first round of voting came back to win the second.
Mr. Lula’s victory was even more surprising given that several of the candidates who failed to make it out of the first round were conservatives whose votes were expected to broadly shift to Mr. Bolsonaro.
