Brazil's main leftist party says former President Lula da Silva will remain its candidate in next month's presidential election. Brazil's Workers' Party said Monday it will present an appeal to the Supreme Federal Court in order to guarantee the presidential candidacy of ex-president Luiz Inacio Lula da Silva. Da Silva has been leading opinion polls, despite being in prison since April for corruption and money laundering. The court's decision could pave the way for da Silva's running mate, former Sao Paulo Mayor, Fernando Haddad. CGTN's Paulo Cabral has details.

Lula da Silva isn't running for president anymore at least for now.

During a marathon session on Friday - and into the early hours of Saturday - Brazil's Superior Election Court annulled the candidacy of the former president on grounds of the country's 'Clean Record Act'. This law prevents politicians convicted of crimes from running for office.

Lula da Silva is now in jail serving a sentence of just over 12 years on charges of corruption.

The Workers' Party still can appeal to the Supreme Court, but legal experts here consider the party's chances of success slim to none.

SILVIO SALATA, PRESIDENT ELECTORAL STUDIES, BRAZILIAN BAR ASSOCIATION "The Supreme Court has already decided on this matter before, so this is something very unlikely to change, even if in my opinion this does violate our Constitution in regard to the presumption of innocence until all appeals are exhausted."

The party has already announced a 'Plan B' candidate if Lula can't run. He's the former mayor of Sao Paulo, Fernando Haddad. Haddad is a 55-year-old politician who served as Lula da Silva's education minister. An economist and lawyer, the media has portrayed Haddad as a moderate - and the 'modern face' of the Worker's Party - untainted by corruption.

PAULO CABRAL SAO PAULO "Fernando Haddad is well-known here in Sao Paulo, but he's not considered a national figure with enough support to win a presidential election on his own. Brazilian analysts say his only chance of victory depends on Lula da Silva's ability to transfer his votes to another candidate. Not only does Lula lead in the polls, he is extending his lead-despite his conviction and arrest."

JOSE ALVARO MOISES POLITICAL SCIENTIST "Lula is a trade union leader who came from a poor-northeastern state, a person who struggled a lot to get where he is. Fernando Haddad is a middle class academic. So the notion that there will be an automatic transfer of votes is wishful thinking. But of course, it could happen: the Workers Party is an important party, very well rooted in the population."

The Workers' Party has until September 11th to officially present another candidate. There's still much uncertainty and the possible outcomes remain wide open in Brazil's elections.

Paulo Cabral, CGTN, Sao Paulo.