SAO PAULO (AP) — Brazilians vote Sunday in a high-stakes presidential election pitting incumbent Luiz Inácio Lula da Silva against Sen. Flávio Bolsonaro, ideological opposites who are each seen as having a shot at an outright victory.

If no candidate gets more than 50% of the vote, the top two vote-getters will head to a runoff on Oct. 25 in Latin America's economic powerhouse. Ten other candidates are expected to garner much smaller numbers of votes on Sunday.

Bolsonaro, 45, is the son of far-right former President Jair Bolsonaro and an ally of U.S. President Donald Trump. Lula, who at 80 is one of the world’s oldest heads of state, is running in his seventh presidential election and has strengthened Brazil's ties with Beijing.

Trump allies have found support in recent years in some Latin American countries, including Argentina, Colombia and Peru.

Almost 159 million Brazilians are eligible to vote in this tense political showdown.

Where Bolsonaro has leaned into his ideological alliance with Trump, Lula has criticized Washington. He has often spoken about risks of U.S. intervention in the Brazilian elections after the Trump administration imposed high tariffs against Brazilian exports, revoked the visa of the country’s ambassador in D.C. and sanctioned a Supreme Court justice who chaired the probe that ended up resulting in the sentencing of Jair Bolsonaro, Lula's predecessor.

Flávio Bolsonaro has touted his proximity to the White House and insisted Brazil needs to strike better deals with the Trump administration, including the rare minerals economy. Brazil estimates its deposits to hold up to 21 million tons, second only to China. Bolsonaro also has campaigned on releasing his father from his 27-year prison sentence for attempting a coup and bringing him back to politics.

Bolsonaro denies he's being helped by the U.S. government. "That narrative won't stick, sorry,” he said at a September campaign event.

Brazilians will also elect 27 state governors, members of state legislatures, all 513 federal congressmen and 54 of the country’s 81 senators in Sunday's vote.

Thomas Traumann, a political consultant based in Rio de Janeiro, says last-minute mistakes by either candidate or by their allies could make all the difference for undecided voters.

“ Polarization in Brazil created a trap. There’s no third candidate. You only have two options, and they fight each other in an atmosphere that becomes worse and worse,” Traumann said. “It is much more a competition of accusations than a competition of proposals.”

Four years ago, Lula beat Jair Bolsonaro by 2.1 million votes — a margin of just under 2 percentage points. At the time, Brazilians were upset with the then-president’s handling of the coronavirus pandemic, his repeated threats against democracy, his attacks on the electronic voting system, and the poor shape of the nation’s economy as inflation was on the rise.

Now, the incumbent faces a tough battle due to an affordability crisis and a corruption scandal that ensnared the same justice who led the investigation into Bolsonaro.

Carlos Melo, a political science professor at Insper University in Sao Paulo, says some voters have grown weary of Lula, who is seeking a fourth nonconsecutive term as president. He is one of the oldest presidents on the continent, along with Trump and Nicaragua's Daniel Ortega, both of whom also are 80.

“Many in the Lula campaign were not expecting such a difficult election a few weeks ago, and it is clear to them that the present election is a tough battle and the next ones, without Lula, could be even more so,” Melo said.

Bolsonaro has seen his political career tainted by several corruption accusations, the latest of them involving a disgraced banker paying him millions of dollars, allegedly to produce a movie on his father's life. More recently, he has been under fire from Roman Catholics who fear he might make too many concessions to his evangelical base.

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