More than 158.7 million Brazilians are eligible to vote Sunday in a presidential runoff that final surveys place inside their margins of error, giving South America’s largest country a choice between a fourth term for President Luiz Inácio Lula da Silva and a return of the Bolsonaro family to power through Sen. Flávio Bolsonaro. The electoral court will begin publishing the count after polls close at 5 p.m. Brasília time, and Brazil’s electronic system is expected to produce a result within hours.

The contest remains genuinely uncertain. A final Datafolha poll put Bolsonaro at 51% of valid votes and Lula at 49%, but its two-point margin of error made that a statistical tie. Separate CNT/MDA, Quaest and Nexus surveys also showed Bolsonaro ahead by one to 1.3 percentage points, all within their margins of error, according to a Reuters review.

A first-round lead without a decisive mandate

Bolsonaro entered the runoff with an advantage from the Oct. 4 first round. Official TSE results gave him 56.1 million votes, or 47.03% of valid ballots, compared with Lula’s 53.9 million, or 45.16%. Neither crossed the majority threshold, while other candidates together accounted for enough votes to decide the second round.

The final polls suggest Lula narrowed the gap without establishing a clear lead. Datafolha interviewed 4,050 voters in 124 municipalities on Friday and Saturday; 95% said their choice was firm, yet its turnout model showed a slightly wider Bolsonaro advantage among people most likely to vote. That makes participation at least as consequential as late persuasion, particularly after 21.08% of the electorate did not vote in the first round.

Turnout divides the candidates’ coalitions

Polling points to two geographically and socially different coalitions. Datafolha found Bolsonaro strongest in Brazil’s Southeast and South and among evangelical voters, while Lula led among lower-income voters, younger adults, Catholics and residents of the Northeast. Those figures describe survey patterns rather than fixed blocs, and subgroup margins of error are larger than the national estimate.

Both campaigns therefore closed by mobilizing supporters in places where turnout could shift the national result. Lula marched with crowds in Rio de Janeiro and São Paulo, while Bolsonaro joined a motorcycle caravan in Belo Horizonte before campaigning in Rio. Minas Gerais, where Bolsonaro led the first round by about five points, remains especially important: no presidential candidate has won without carrying the state since Brazil returned to democracy in the 1980s, Reuters reported.

The choice extends beyond party control

Lula, 80, is seeking a fourth nonconsecutive term after serving from 2003 through 2010 and returning to office in 2023. His campaign emphasizes income support, tax and debt relief, labor protections and protection of the Amazon. His political weakness is equally clear: frustration over crime and living costs has eroded approval, and Bolsonaro’s first-round lead showed that many voters want a break from the incumbent.

Flávio Bolsonaro, 45, has framed his campaign around public security, conservative social policy and alignment with the agenda of his father, former President Jair Bolsonaro. He has proposed large prisons, tougher treatment of criminal organizations and adult prosecution for some 16-year-old defendants. An AP analysis also notes that he has questioned human-caused climate change and faces an investigation involving alleged corruption, money laundering and tax evasion; he has not been convicted in that matter.

Foreign policy and the Amazon are on the ballot

The outcome will influence more than domestic policy. Brazil is the largest economy and most populous country in Latin America, a major agricultural exporter and home to most of the Amazon rainforest. A Lula victory would preserve a government that has sought a more independent position between Washington, Beijing and the Global South. Bolsonaro has cultivated ties with U.S. President Donald Trump and would likely move Brasília closer to Washington on security and regional politics.

Those ties became part of the campaign after U.S. tariff actions and political support for the Bolsonaro family prompted Lula to accuse Washington of interference. The candidates also differ sharply on environmental governance. Lula presents forest protection as a national and diplomatic priority, while Bolsonaro has emphasized stopping illegal deforestation without accepting the broader scientific consensus on human-driven climate change. The president cannot control the Amazon alone, but federal enforcement, land policy and international climate commitments shape what happens on the ground.

A fast count will settle a long political argument

Brazil’s election authority says voting will also include gubernatorial runoffs in five states and the Federal District, plus supplemental mayoral elections in seven municipalities. Voting is mandatory for most adults, although eligible voters who missed the first round may still participate Sunday. Valid-vote totals exclude blank and spoiled ballots, the same convention used by the polls when they publish head-to-head percentages.

The central uncertainty is turnout, not whether one late poll can predict the winner. The surveys consistently describe a race within sampling error, while the first round established only a narrow Bolsonaro advantage. Sunday’s count will determine whether Lula completes another political recovery or whether Brazilian voters entrust the presidency to a second generation of the Bolsonaro movement. Either result will immediately reset Brazil’s approach to security, social spending, climate policy and its relationships with the United States and the wider region.