After the most contentious election race since the end of military rule in 1985, Brazilians will Sunday choose their next president, weighing a decade of social progress against a yearning for economic revival.
Brazilian president and presidential candidate for the Workers Party, Dilma Rousseff (R) greets a child in Porto Alegre, Brazil, on October 25, 2014
Final opinion polls Saturday showed leftist incumbent Dilma Rousseff a narrow favorite with a four- to six-point advantage over center-right Aecio Neves in the race to lead the world's seventh-largest economy.
A former guerrilla jailed and tortured for fighting the country's 1964-1985 military regime, Rousseff -- Brazil's first woman president -- has needed all her battling qualities to claw back the advantage on Neves, the choice of the business world.
Sunday's vote is widely seen as a referendum on 12 years of government by her Workers' Party (PT) -- eight under working-class hero Luiz Inacio Lula da Silva and four under Rousseff, who has presided over anemic growth culminating in recession.
The PT has endeared itself to the masses though, particularly in the impoverished north, with landmark social programs that have lifted 40 million people out of poverty, increased wages and brought unemployment to a record-low 4.9 percent.
But after Brazil benefited from an economic boom during the Lula years, the outlook has darkened since Rousseff won the 2010 election, the year economic growth peaked at 7.5 percent.
Rousseff, 66, has overseen rising inflation and a recession this year. She also faced massive protests last year against corruption, record spending on the World Cup, and poor services, notably education, healthcare and transport.
- Trading punches -
She has further been battered by a multi-billion-dollar embezzlement scandal implicating dozens of politicians -- mainly her allies -- at state-owned oil giant Petrobras.
Right-wing news magazine Veja on Friday quoted a suspect in the case as saying Rousseff and Lula personally knew of the scam. She roundly denied the claim and threatened to sue.
Before the October 5 first-round vote, Rousseff fended off environmentalist Marina Silva, who initially surged in opinion polls with her vow to become Brazil's first "poor, black" president, having dramatically entered the race after running mate Eduardo Campos died in a plane crash.
No sooner had the PT electoral machine dispatched Silva -- who exited the contest with 21 percent to Rousseff's 42 percent and Neves's 34 percent -- than the incumbent had to beat back Neves, who opened a brief lead in surveys.
With the candidates fighting for every vote in this sprawling country of 202 million people, the campaign took on a level of animosity not seen since the return to democracy.
Rousseff accused Neves of nepotism as governor of Minas Gerais state, then played up a report he once hit his then-girlfriend in public.
And she suggested the Social Democrat was driving "drunk or on drugs" when he refused to take a breathalyzer during a 2011 traffic stop.
Neves, a 54-year-old senator and the grandson of the man elected Brazil's first post-dictatorship president, responded in kind, accusing Rousseff of lying, incompetent economic management and "collusion" in the Petrobras kickbacks.
- Middle class key -
Brazil's 142.8 million voters enter election day divided along social lines.
"Yet in reality, the two candidates don't have widely differing policies -- four years is quite a short time to turn the ship around," Lia Valls, an economist at the Getulio Vargas Foundation specializing in Brazilian trade, told AFP.
While the poor back the PT, Brazil's elite are exasperated with interventionist economic policies such as gasoline price controls and high taxes.
The key battleground is for votes in the industrialized southeast, the cradle of the million-strong protests last year where a growing middle class is making growing demands.
They are torn between voters loyal to the PT's transformative social policies and those frustrated on the economy.
"The country is divided, and whoever wins will need to reach out to the opposition," said Lourdes Casanova, an emerging markets specialist at Cornell University in New York state.
Voters are also electing governors in run-offs in 14 states where no candidate took more than 50 percent in the first round.
Polls open at 8:00 am (1000 GMT in Rio) and results are expected shortly after the 5:00 pm close, thanks to a sophisticated electronic voting system.
Brazilian authorities have deployed 35,000 military police in Rio de Janeiro ahead of the run-off after a string of attacks on police and clashes between drug gangs.
Across the country, the army is beefing up security in 224 cities for the vote.
Voting is compulsory in Brazil, Latin America's largest democracy.