Brazilians vote Sunday in an election Argentina's president has openly tried to influence. Javier Milei joined Flávio Bolsonaro's campaign launch in São Paulo on 25 July, where La Nación reported that he called the senator a friend and President Lula a "thief." Now officials in Buenos Aires are weighing what a Bolsonaro win would mean for Milei's standing with Donald Trump.
The argument comes from Argentine news site iProfesional, which published political writer Mariano Obarrio's analysis on Saturday 3 October. Drawing on sources in Argentina's foreign ministry, the report said a Flávio Bolsonaro victory could give Milei an ideological ally next door. It could also cost him his special place with Washington.
A Neighbor Ten Times Too Big to Ignore?
One foreign ministry source put it bluntly. "If Bolsonaro wins, the United States will give more room to Bolsonaro than to Milei," the source told Obarrio. The reason is scale: "Brazil weighs more as a country and because of the size of its economy." Brazil has about 213 million people, more than four times Argentina's population, and Latin America's largest economy.
Officials at the Casa Rosada, the presidential palace, said they "would love Bolsonaro to win, but 'worry' is not the word." According to the report, Milei was wary of intervening directly in the campaign. He hadn't ruled out traveling to Brazil if Flávio Bolsonaro won the first round.
Benjamin Gedan of the Stimson Center, a Washington think tank, made a similar point to Argentine outlet TotalNews. Gedan, a former White House adviser on South America, called Flávio Bolsonaro "as MAGA as Milei." He said the Brazilian was "equally committed" to becoming Washington's main South American ally. Flávio has promised Brazil would join the Shield of the Americas, a U.S.-led security initiative Argentina already belongs to.
What Rides on the Relationship
The diplomatic damage is already visible. Brazil downgraded its diplomatic representation in Buenos Aires in August, and La Nación reported that neither ambassador had returned to post. Milei's relations with Lula have collapsed.
The economic stakes are large. Two-way trade between the two countries reached US$31.2 billion in 2025, a 13-year high, according to the Rosario Board of Trade. Argentina exported US$12.8 billion in goods to Brazil and imported US$18.4 billion, leaving a deficit of about US$5.7 billion. Cars, car parts, wheat and fuel account for much of that trade, Forbes Argentina reported.
Flávio Bolsonaro has courted Argentina. In June, he promised Brazil would "return to being a brother to Argentina." His economic coordinator, Daniella Marques, said his plan draws on Milei's approach. A Bolsonaro victory could end the diplomatic freeze. A Lula victory would leave Milei facing a neighbor he has repeatedly insulted.
Limits of the Analysis
The concern reflects the judgment of unnamed officials, not a signal from Washington. Time reported that Trump hadn't endorsed Flávio Bolsonaro, though he called Brazil's vote very important. iProfesional described a possible double effect: Milei could gain a like-minded partner while sharing Trump's attention with a much larger country.
Polls were scheduled to close at 17:00 Brasília time, also 17:00 in Buenos Aires and 20:00 UTC. If no candidate wins more than half the valid votes, the top two meet again on 25 October.
Why This Matters: Argentina's president has tied his diplomacy to one candidate in a neighbor's election. Brazil buys much of what Argentina exports, yet its diplomatic presence in Buenos Aires has been downgraded. With US$31.2 billion in trade at a 13-year high, and cars, wheat and fuel at its core, relations between governments aren't an abstraction. From a perspective that favors stable, rules-based cooperation, trade on that scale argues for working relationships that survive any single election. The reporting also shows how much a smaller democracy's foreign policy can hinge on personal alliances and the attention of a larger power. Either way, officials in both capitals will have to deal with each other once the votes are counted.