SAO PAULO, Brazil (AFP) — Even behind bars, Brazil’s Luiz  Inacio Lula da Silva will secure his leftist party’s nomination Saturday

and continue to overshadow more likely candidates in the country’s most unpredictable presidential election for decades.

Saturday will see three big party conventions, two months before the first round of voting on October 7

in Latin America’s dominant economy.

Centre-left environmental campaigner Marina Silva will get the nomination of her Rede party in Brasilia. Also in the capital, former Sao Paulo governor and establishment heavyweight Geraldo Alckmin will secure the nod from the centre-right Brazilian Social Democratic Party, or PSDB.

But while both Silva and Alckmin are serious contenders in a battle against controversial right-winger Jair Bolsonaro, it’s the third convention taking place in Sao Paulo that will suck up much of the attention.

The Workers’ Party, founded by Lula, will nominate him in his bid to return to power for a third term.

Never mind that he started serving a 12-year sentence for corruption this year. Never mind that he is likely to be barred from the ballot.

Despite the scandals – which he and his supporters believe have been artificially stoked to keep him out of the election – Lula is still unquestionably the biggest beast in Brazilian politics.

Polls show him with near double the support of all other main candidates in a first round, crushing any runner up in the second decisive round two weeks later

.

Lula and his Workers’ Party, which underpinned his domination of Brazil during two terms in 2003-2010, believe he’s no yesterday’s man.

“He’s still the leader,” rubs in the Workers’ Party’s latest election ad online, featuring a picture of the smiling 72-year-old, dressed in his trademark black T-shirt and suit jacket.

Lula is waiting for final court judgment on whether he can run. It doesn’t look good: under current law anyone losing an appeal of a criminal conviction is not allowed on the ballot.

So despite the left’s almost cult-like enthusiasm for Lula, there will be close attention Saturday

to the choice for vice president – a figure who could end up standing in for the imprisoned leader.

One high-profile possibility is former Sao Paulo mayor Fernando Haddad. A powerful politician, he has signed on to Lula’s legal team, giving him easy access to the prison, and he would be well placed to inherit Lula’s electorate.

But analysts say the party could yet choose a lesser figure, deliberately throwing the election in order to underline the argument that Lula’s exit robbed Brazilians of their democratic choice.

Alckmin has already named Senator Ana Amelia, who is expected to help him in the south of the country and eat into conservative support for Bolsonaro.

If Alckmin has gone for a female VP, Silva has struck a pact with a man, Eduardo Jorge, from Brazil’s Green Party.

Bolsonaro, who has positioned himself as a radical right-winger appealing to Brazilians’ fury over crime and corruption, has yet to find his running mate. Names thrown around in Brazilian media reports have included a former astronaut, a member of the royal family and a general.