What is at stake in Brazil's elections?

A deeply polarized Brazil heads to the polls on Sunday to choose between two starkly different visions for the country proposed by leftist President Luiz Inacio Lula da Silva and right-wing senator Flavio Bolsonaro.

These are the key issues at stake:

- Leftist holdout, or join rightward march -

Latin America has swung sharply to the right in recent years, in elections in Argentina, Chile, Bolivia, Colombia, and Peru.

A Lula victory would keep Brazil as a major leftist bastion in the region, alongside Mexico, while a Flavio Bolsonaro win would see the country join the shifting tide.

Oliver Stuenkel, a professor at the Getulio Vargas Foundation, downplayed the importance of ideology in regional relations as more "rhetorical than substantive."

Lula, a veteran and pragmatic leader, maintains normal ties with the right-wing leaders of Chile, Bolivia, and Paraguay.

Even ties with Argentina, a strategic partner whose libertarian President Javier Milei has criticised Lula, have changed little, Stuenkel told AFP.

- Relations with Washington -

Ties with Washington have grown frosty under Lula.

President Donald Trump is an ally of far-right former president Jair Bolsonaro, father of the current candidate.

His administration has imposed tariffs on Brazilian products and sanctions on judges and other officials.

If Lula wins, Washington will likely continue resorting to threats and targeted tariffs to curb ties with China, said Regiane Bressan, a professor of International Relations at the Federal University of Sao Paulo.

The US is Brazil's second-largest trading partner, behind China.

A Flavio Bolsonaro presidency would have more alignment with Washington, "at least rhetorically," said Bressan.

- A test for democracy -

Jair Bolsonaro's presidency from 2019 to 2022 put Brazil's democracy to the test.

He spent years confronting institutions, attacking the Supreme Court, and casting doubt on the country's electronic voting system.

After losing the election, Jair Bolsonaro and his allies plotted to overturn the result and prevent Lula from taking office.

The former president was convicted in 2025 of attempting a coup and is serving a 27-year sentence under house arrest.

In January 2023, thousands of his supporters invaded the headquarters of Brazil's three branches of government in Brasilia, seeking to overturn the election and trigger military intervention.

Flavio Bolsonaro has also cast doubt on the electronic voting system, but later said he would respect the results.

He has vowed to seek amnesty for his father and his convicted supporters, if elected.

Lula defended Brazil's "modern and robust" electoral system at the United Nations last week and warned that he would not allow "enemies of democracy" to undermine popular will.

- The future of the Supreme Court -

Sunday's election will also renew the Chamber of Deputies and two-thirds of the Senate, which has held a conservative majority in recent years.

This is significant because the next president will appoint up to four of the eleven Supreme Court justices, who must be confirmed by the Senate.

In April, the upper house rejected Lula's nominee for the high court. This had not happened in over a century.

Flavio Bolsonaro has lashed out at the court and called for the removal of Justice Alexandre de Moraes, who presided over his father's trial.

The court has also been thrown into disarray as investigations have scrutinized links between several justices, their relatives or associates, and jailed, fraud-accused banker Daniel Vorcaro.

- The Amazon and climate change -

Brazil plays a pivotal role in the fight against climate change as home to much of the Amazon rainforest.

However, the issue has been absent on the campaign trail.

Deforestation dropped sharply during Lula's administration, and he vows to end it by 2030.

However, he has come under fire for backing oil exploration near the mouth of the Amazon River.

Flavio Bolsonaro has avoided attributing global warming to human activity.

Nevertheless, he has vowed to end deforestation by 2029, though his support for agribusiness has cast doubts on whether he will follow through.