Brazilians went to the polls Sunday in a high-stakes presidential election pitting incumbent Luiz Inácio Lula da Silva against Sen. Flávio Bolsonaro, the son of former President Jair Bolsonaro and a prominent ally of President Donald Trump.

Lula, 80, is seeking a fourth nonconsecutive term in office, while Bolsonaro, 45, is making his first presidential bid. The two candidates represent sharply different political camps in a contest that has become increasingly focused on the economy, national sovereignty, foreign relations and the legacy of Brazil’s previous administration.

A candidate must receive more than 50% of the valid vote to win the presidency outright. If neither Lula nor Bolsonaro reaches that threshold, the two leading candidates will meet in a runoff scheduled for Oct. 25. Recent polling has shown the contest to be close, with neither candidate consistently reaching a majority.

Bolsonaro has emphasized his relationship with Trump and argued that Brazil should improve its dealings with the United States, including cooperation involving the country’s critical-minerals resources. Brazil estimates it holds as much as 21 million tons of rare-earth deposits, second only to China.

He has also campaigned on securing the release of his father, who is serving a 27-year prison sentence after being convicted of attempting to overturn his 2022 election defeat. Flávio Bolsonaro has pledged to seek his father’s return to political life if elected.

“Brazil needs change. Brazil can’t stand so much suffering,” Bolsonaro said after voting Sunday in Rio de Janeiro.

Lula, meanwhile, has criticized U.S. involvement in Brazilian affairs and has warned about what he describes as the risk of Washington interfering in the election. Tensions between Brazil and the Trump administration have increased following U.S. tariffs on Brazilian exports, the revocation of the Brazilian ambassador’s U.S. visa and sanctions against a Brazilian Supreme Court justice involved in the investigation that led to Jair Bolsonaro’s conviction.

Lula has also strengthened Brazil’s relationship with China during his current term, adding an international dimension to the presidential contest as Brazil balances ties with its two largest global partners.

The election comes after Lula defeated Jair Bolsonaro by less than two percentage points in 2022. The elder Bolsonaro subsequently challenged the country’s electronic voting system and was later convicted over an effort to overturn the election result.

This year, Lula faces voter frustration over the cost of living and a corruption scandal involving figures connected to the Brazilian judiciary. Political analysts say those issues have made the race substantially more competitive than Lula’s campaign expected.

Thomas Traumann, a political consultant based in Rio de Janeiro, said the country’s intense polarization has left voters largely choosing between two opposing political camps rather than a broader field of alternatives.

Beyond the presidency, Brazilians are also electing 27 state governors, members of state legislatures, all 513 members of the lower house of Congress and 54 of the Senate’s 81 seats.

The outcome could have consequences beyond Brazil’s borders as the country weighs its economic and diplomatic relationships with the United States and China while voters decide whether to extend Lula’s time in office or return the Bolsonaro family to the presidency.