The most uncertain presidential race in recent Brazilian history kicked off Friday, with center-left candidate Ciro Gomes the first major party hopeful to officially throw his hat into the ring.
But still topping opinion polls is former leftist leader Luiz Inacio Lula da Silva, who has been in prison on a corruption conviction since April.
Should the race be Lula-free, controversial far-right lawmaker Jair Bolsonaro -- infamous for his misogyny, homophobia and nostalgia for military dictatorship -- is currently the frontrunner.
It makes for the perfect political storm in Brazil, Latin America's biggest economy, which is still struggling to emerge from two years of recession -- and struggling to put years of government-linked corruption scandals in the past.
Gomes, a 60-year-old lawyer and sharp-tongued political animal who has joined and left many a party over the years, launched his candidacy at the Democratic Labor Party (PDT) convention in Brasilia.
But he quickly suffered a setback as several centrist parties formed an united front and said they will back one of his rivals, former Sao Paulo governor Geraldo Alckmin of the center-right Brazilian Social Democratic Party (PSDB).
Gomes is hoping to be the main candidate for Brazil's political left in the absence of Lula, a former union leader who served as president from 2003 to 2011, but whose candidacy will likely be blocked by election officials.
Lula has said his conviction is a political sham designed to keep him from running for a third term, and his Workers' Party (PT) plans to officially announce his candidacy on August 4.
"In this context, it is difficult to make predictions. The relative crisis faced by the Workers' Party could benefit Ciro Gomes," explained Ricardo Sennes, of consultancy Prospectiva.
But Sennes also said anti-Lula sentiment could boost Bolsonaro, who this year joined the Social Liberal Party (PSL).
- What happens if Lula can't run? -
With Lula sidelined, Bolsonaro's chances are greatly improved, according to opinion polls.
In a late June poll on a Lula-free race, he came out on top with 17 percent of intended votes, followed by black ecologist Marina Silva (13 percent), Gomes in third (eight percent), and then Alckmin (six percent).
Brazil is home to no less than 35 political parties, and convention season will run through August 5. The parties then have until August 15 to name their candidates.
Sometimes, the various groups form alliances -- even if they are somewhat counter-intuitive -- to maximize their campaign prospects.
Public campaign funds and airtime on Brazil's main television channels can depend on a coalition's weight in parliament.
The fact that campaign financing from businesses is forbidden during the election season makes those deals all the more crucial.
Following Gomes's declaration, the next key date in the election cycle is Sunday, when all eyes will be focused on Bolsonaro.
The far-right populist will need to decide the other name on his ticket, having been rejected by several of his vice-presidential picks.
Deeply unpopular current President Michel Temer will not be running again, with his party instead (MDB) instead set to name former finance minister Henrique Meirelles as its candidate on August 2.
The two main governing parties in Brazil since the country returned to democracy -- the Workers' Party and the PSDB -- will meet at the last minute, on August 4, where they will announce Lula, against all odds, and Alckmin as their respective candidates.
Brazilian presidential candidate Ciro Gomes was the first to formally enter the race, but he has already hit a snag, with the announcement of a centrist alliance that includes one of his main rivals
The wild card in Brazil's presidential election is former leader Luiz Inacio Lula da Silva, who has been jailed for corruption since April but still leads opinion polls