Brazilian President and presidential candidate Dilma Rousseff waves to supporters during a campaign rally in Sao Paulo, Brazil, on September 20, 2014
Brasília (AFP) - Less than two weeks before Brazil's presidential vote, corruption concerns dominate the campaign, amid allegations that leading politicians benefited from huge kickbacks on oil deals by state-owned energy giant Petrobras.
Voters are aghast at claims by a former Petrobras director that dozens of lawmakers and three state governors -- mostly from the ruling Workers Party (PT) and its allies -- took cuts of contracts worth hundreds of millions of dollars.
"This affair hands ammunition to the opposition," political scientist Cristiane Jalles, of the Juiz de Fora University, told AFP.
President Dilma Rousseff, seeking a second term in the October 5 poll, is struggling to hold off environmentalist challenger Marina Silva, campaigning for the Socialist Party.
Silva has headed the leading opposition ticket since her late Socialist running mate Eduardo Campos died in an August 13 plane crash while campaigning.
Even though the Petrobras allegations remain unproven, the opposition has rushed to decry an affair it dubs "Mensalao 2."
Mensalao Mark One was a cash-for-votes scandal during the first term in office of Dilma's predecessor as president and PT mentor Luiz Inacio Lula da Silva.
The original mensalao scandal, named after a monthly allowance for officials, dealt a blow to the PT's image.
Although Lula's personal reputation remained intact, several of his associates were sentenced and jailed last year.
Silva, who polls show is neck-and-neck with Rousseff for a second round contest on October 26, has accused the government of trying to "destroy Petrobras," an iconic company for Brazilians.
"Corruption has always been present at elections and we can't simply ascribe that to the PT and its allies. There have been cases too within the opposition," says Gil Castello Branco, an official with Open Accounts, a non-governmental public spending watchdog.
Less than a year into her tenure, Rousseff took a hard line on financial malpractice when she dismissed from the cabinet seven ministers accused of embezzlement or other forms of corruption.
- 'Clean candidate' -
Some aspects of the Brazilian political system provide fertile ground for corruption to take root -- not least the corporate financing of election campaigns.
The system also forces the party topping the poll to govern through alliances with other parties.
These secure top posts in Brazil's main state enterprises whose huge resources they manage with little outside interference, Castello Branco told AFP.
As well as electing a president on October 5, voters will also vote for 27 state governors, 27 senators, 513 congressmen and 1,035 regional lawmakers.
Those elected will be the first to serve following "Clean Record" legislation which demands all those standing be "clean candidates" with no instances of illicit gain on their record.
- Spectacular scalp -
The law has already claimed a spectacular scalp with the resignation of Jose Roberto Arruda, who had been regarded as favorite to land the Brasilia governorship.
Arruda, who had already been governor, quit in 2010 and was then jailed after television footage showed him apparently receiving bribes.
Another to fall victim to the law was former Sao Paulo governor Paulo Maluf, whose 2014 hopes were dashed, owing to Interpol issuing a red notice warrant against him over allegations of grand larceny and illegal property possession.
In all, the 2011 Clean Record act has prevented some 250 candidates from standing.
Last year saw more than a million Brazilians take to the streets to protest corruption and several organizations grew out of the movement.
One group aiming to combat electoral corruption has launched a mobile phone application to allow users to check on how transparent each candidate is.
"There is less tolerance for corruption," said Bruno Speck, political scientist at Sao Paulo University.
But he had a word of warning.
"The citizen's capacity for indignation has grown quicker than that of the authorities to find solutions," he said.
"This will be the big challenge of the next 20 years along with the struggle against poverty or protecting the environment."