Donald J. Trump’s claims of election fraud already helped inspire one South American leader, former president Jair Bolsonaro of Brazil, to sow doubt about the security of his nation’s elections, leading to a riot in Brazil’s capital this year.
Now, 1,500 miles to the south, there is a new Latin American politician warning of voter fraud with scant evidence, undermining many of his supporters’ faith in their nation’s election this Sunday.
Javier Milei, a far-right libertarian economist and television personality, is competing to become Argentina’s next president in a runoff election. On the campaign trail, he has embraced comparisons to Mr. Trump and Mr. Bolsonaro, and, like them, has repeatedly warned that if he loses, it may be because the election was stolen.
Mr. Milei has claimed, without evidence, that stolen and damaged ballots cost him more than a million votes in a primary election in August, or as much as 5 percent of the total.
He said similar fraud also may have rigged the first round of the general election on Oct. 22, when he placed second with 30 percent of the vote. “The irregularities were so big that it puts the results in doubt,” he said in a television interview last week.
On Wednesday, his campaign escalated its accusations. Mr. Milei’s sister, who runs his campaign, filed a complaint with a federal judge claiming “colossal fraud” and saying that in the earlier votes, unnamed Argentine officials changed ballots for Mr. Milei to his opponent. They said the information came from anonymous sources.
Mr. Milei’s rise from a fiery television pundit to a political leader on the verge of Argentina’s presidency has already shaken the politics of this nation of 46 million. His radical promises to ditch Argentina’s currency for the U.S. dollar and close the nation’s central bank have left Argentines bracing for what could happen if he wins.
But now, with his pre-emptive claims of fraud, Argentines are also bracing for what could happen if he doesn’t.
Polls suggest a dead heat between Mr. Milei and his opponent, Sergio Massa, the center-left economy minister.
Many of Mr. Milei’s supporters are already crying foul, blaming fraud for his second-place finish last month and taking to the streets at least three times to protest what they say are the left’s plans to steal the vote. On Thursday, his supporters announced plans to protest outside the nation’s electoral authority on Election Day.
So far, protests have been relatively small and peaceful, but election observers note that Mr. Milei is still in the race.
“I am not worried that the Argentine electoral system is at risk,” said Facundo Cruz, an Argentine political scientist who has tracked the fraud claims. “But I am worried that certain practices we’ve seen in the United States and Brazil may be repeated.”
Argentina’s predicament suggests that Mr. Trump’s efforts to overthrow the 2020 U.S. election not only left a lasting mark on American democracy, but are also still reverberating far beyond U.S. borders, where some political leaders are turning to fraud as a new potential excuse for electoral defeat.
“In 40 years of democracy, we’ve never had serious criticism or any idea of fraud like they are claiming now,” said Beatriz Busaniche, head of the Vía Libre Foundation, an Argentina nonprofit that has worked to improve the nation’s voting systems. (Argentina was ruled by a military dictatorship from 1976 to 1983.)
“All the people who believe in the electoral system, democracy and transparency are all very worried,” Ms. Busaniche added.
Argentine election officials say there has been no evidence of fraud. In the Oct. 22 vote, they received 105 total reports of missing or damaged ballots, a typical number.
Election officials said they have also not received any formal complaints from Mr. Milei’s campaign regarding fraud. Argentina’s electoral authority, in a statement, called his statements “baseless claims of fraud that misinform the public and undermine democracy.”
In Argentina, citizens vote by inserting a paper ballot of their preferred candidate into an envelope and dropping the sealed envelope into a box. Campaigns distribute their ballots to the polling stations. Mr. Milei and his allies claim that people have been stealing his ballots from polling stations, preventing his supporters from casting a vote for him.
When pressed, though, Mr. Milei and his campaign have failed to produce much evidence. After Argentina’s electoral prosecutor called on Mr. Milei’s campaign to present proof, the campaign said it responded with videos and photos from social media.
The man coordinating Mr. Milei’s response to election officials, Santiago Viola, the campaign’s national legal director, said in an interview that he had 10 to 15 written complaints from people who said ballots with Mr. Milei’s name were missing from their polling stations.
Mr. Viola said he believed campaign officials in other parts of the country collected other complaints, but he had not seen them. He could not verify another campaign official’s claim last month that there were 4,500 reports of missing ballots. More than 26 million people voted last month.
“Javier has a better handle on the numbers than me,” Mr. Viola said, referring to Mr. Milei.
Mr. Milei’s says there are “studies’’ showing he was robbed of 5 percent of the vote in the primary election, but he has not shared them.
Mr. Milei has said that one sign of fraud is that in voting, some polling stations reported no votes for him. “That is statistically impossible,” he said. In reality, the three top candidates last month all tallied zero votes at nearly the same number of polling stations — roughly 100 each — not counting stations that recorded no votes at all. There are 104,520 stations.
“I didn’t come out claiming fraud,” Mr. Massa, Mr. Milei’s opponent, said in an interview. “There can be polling stations where no one votes for you.”
Mr. Massa said that Mr. Milei is following a familiar playbook. “This is the same methodology as Bolsonaro, the same methodology as Trump,” he said.
Mr. Milei has shown a proclivity for conspiracy theories. He has called climate change a socialist plot. He has said he doubts the results of the 2020 and 2022 elections in the United States and Brazil. And he has claimed that the subsequent mob attacks on the American and Brazilian capitol buildings had nothing to do with Mr. Trump or Mr. Bolsonaro.
“What happened in Brazil was shown to have been set up by the Brazilian government itself,” he told The Economist in September. Yet there is clear, ample evidence that Mr. Bolsonaro’s supporters raided Brazil’s capitol in a bid to overturn Mr. Bolsonaro’s election loss.
As a presidential candidate, Mr. Milei has far less power than Mr. Trump and Mr. Bolsonaro did as incumbent presidents when they claimed fraud. Yet in both the United States and Brazil, the government institutions they controlled largely resisted the fraud claims.
Instead, it was their supporters — who had listened to claims of voter fraud for months — who raided the buildings of power.
After the results of the first round came out last month, Julian Ballester, 21, a construction worker, stood outside Mr. Milei’s election-night headquarters, convinced the numbers were rigged. “They threw out many ballots,” he said, saying he had seen photos in WhatsApp groups. “The fraud is obvious.”
Argentina has grown more tense over the past year as the economy has cratered. Annual inflation exceeds 140 percent, while poverty and hunger have risen. Mr. Milei has built his campaign in part on a claim that a shadowy cabal of elites, led by Mr. Massa, is stealing from average Argentines.
Last year, a man driven by conspiracy theories pulled the trigger on a gun inches from the face of Argentina’s vice president, Cristina Fernández de Kirchner, Mr. Massa’s political ally.
The gun malfunctioned and did not fire.
Mr. Milei said this week that his campaign planned to combat fraud on Sunday by arming his campaign’s 103,000 election monitors with ballots, so they could replace stocks in polling stations if any are stolen.
It was sad the campaign needed to take such measures, Mr. Milei said. “Do you realize the madness we’re living in?”