Two frontrunners, an unpredictable race

Sunday's vote is one many believe will decide far more than who governs Latin America's largest country for the next four years. Other candidates appear on the ballot, but the contest has hardened into a fight between two leading names, as recent Latin American elections so often have; across the final stretch, Lula and Flávio Bolsonaro have traded the front-runner position, leaving the result genuinely unpredictable.

• •Lula, the 80-year-old leftist incumbent, is chasing a fourth non-consecutive term.
• •Flávio Bolsonaro, 45, is a far-right senator and the son of former president Jair Bolsonaro; his only previous run for executive office, Rio's 2016 mayoral race, ended in fourth place.
• •Analysts describe a congressman known chiefly for his family name and for corruption allegations - some shelved, others still under investigation - as a serious challenger to a three-time president.

Seven straight wins and the last holdout

Shortly after his September speech to the UN general assembly, Donald Trump brought a dozen like-minded Latin American leaders to New York and boasted that, since his second term began, rightwing candidates had won every one of the seven presidential elections the region had held. Most of those around the table lead the Shield of the Americas, a coalition of 15 right- and far-right-governed countries built to fight the drug cartels. He told most of the Shield's leaders:

The streak's scale shows in what is left of the map: between those victories and the US takeover of Venezuela, which captured Nicolás Maduro, only six Latin American countries still have leftwing governments - Brazil, Mexico, Uruguay, Guatemala, Cuba and Nicaragua. And because Mexico sits on the US border and is tied to it by a one-of-a-kind economic relationship, analysts cast Brazil as the last country in the region still able to say "no" to Trump's whims.

Pedro Telles, a professor at the School of International Relations at Brazil's FGV university, said Trump "really does take seriously the idea that the Americas should be his back yard". If Flávio Bolsonaro wins, Telles added, it would land as a real blow to the left and give the far-right agenda a major lift globally.

Sandra Borda Guzmán, an associate professor of political science at Colombia's Universidad de los Andes, said "There is a lot at stake": rather than expanding the region's autonomy, a far-right victory would bind it unconditionally to the dictates of the US.

Michael Shifter, an adjunct professor at Georgetown University's School of Foreign Service, put it most compactly: "Brazil is a big prize". With conflicts running in Iran, Ukraine and Israel-Palestine, he noted, US foreign policy is faring badly almost everywhere else - a Bolsonaro win would let Trump proclaim, triumphantly, an "almost completely aligned region".

The war on drugs and the fight over minerals

Where the frontrunners divide most sharply is the US - above all over the "war on drugs", now Trump's main foreign policy for the region. Dozens of airstrikes on boats carried out under it have killed more than 230 people, and the campaign also runs joint operations on land involving US military personnel.

• •Flávio Bolsonaro has pledged to join the Shield of the Americas and run crime with an "iron fist".
• •Lula objects on sovereignty grounds: it is, he said, "sad to see the inferiority complex of Latin American presidents" in the Trump-created coalition.
• •Relations between Lula and Trump have swung between not speaking and public warmth - and currently sit at a low point.
• •The Brazilian president and Democratic members of the US Congress say Washington has been working to tilt the contest in Bolsonaro's favour.

Trump used the coalition's latest meeting to point to the region's "tremendous natural wealth", making clear that security is not all this is about, and insisted it could not "be taken over by hostile outside powers" - remarks widely understood as aimed at China.

Washington set a price for withholding tariffs: privileged access to Brazil's rare earths and critical minerals. Lula refused. Flávio Bolsonaro has made the opposite offer, pitching Brazil's natural resources as the "solution" that would let the US end its dependence on China.

The home record and a father who cannot run

At home, voters weigh a mixed ledger: unemployment, poverty and inflation have fallen and average incomes have risen, but household debt has climbed with them - a rise many attribute to online betting, an activity Jair Bolsonaro left unregulated and Lula banned days before the vote.

• •Corruption allegations, still under investigation, have hit Lula's campaign, involving his son and a former aide.
• •A separate scandal involving supreme court justices with no connection to Lula may nonetheless have rubbed off on the president.

Flávio Bolsonaro is on the ballot only because his father cannot be: Jair Bolsonaro, convicted of attempting a coup to overturn his defeat by Lula in the 2022 election, is under house arrest. For Shifter, "Democracy is also kind of on the line here" - and this, he argues, is not just one more country moving right, but "a right that has a very problematic relationship with democracy".

If no candidate passes 50% plus one of the vote, the result is settled in a runoff on 25 October.