RIO DE JANEIRO — President Barack Obama once called him "the most popular politician on earth." That politician will find out this week whether he is still on track to retake the Brazilian presidency — or move one step closer to a prison cell.

Luiz Inácio Lula da Silva, who goes simply by "Lula," heads to court on Wednesday to appeal his 2017 conviction on corruption and money laundering charges, part of a broader anti-corruption probe that ensnared dozens of business and political elites. For Latin America's largest nation, the verdict will be momentous, and could potentially determine the course of the 2018 presidential race.

A hero of the global left who led Brazil from 2003 to 2011, Lula is currently the early front-runner in the race. If his conviction is struck down, it could eliminate one — but not all — major obstacles on his path to victory. 

If the ruling is upheld, the panel of three judges has the power to start proceedings that could send the 72-year-old to jail. Most analysts see that as unlikely, however, saying that due to his age, the judges would probably allow Lula to keep fighting the charges as a free man. 

Nevertheless, a ruling against him would severely complicate, if not immediately end, his presidential ambitions. The Brazilian constitution bans convicted criminals who have lost appeals from running for office. But further appeals to higher courts — up to and including the supreme court — could help Lula find a way to continue his campaign.

Experts say a protracted case could set the stage for a dramatic legal battle in which his eligibility to run might not be fully determined until September — a month before the October elections. 

"The trial is another step in a long path, but if he loses this, [overturning the decision] is going to be hard," said Oscar Vilhena Vieira, professor of constitutional law at the Fundação Getulio Vargas, a Sao Paulo-based university.

No matter the outcome, protesters from the left and right across this vast nation of 208 million are already preparing to take to the streets — be it in celebration or rage.

"His base sees him as a godlike figure," said Heni Ozi Cukier, a political scientist at ESPM University, also in Sao Paulo. "If Lula is in the election, the election becomes about who can beat Lula. Without Lula, it's a very open playing field."

Lula's 2017 conviction stems from Brazil's sweeping, four-year corruption probe known as "Operation Car Wash" — a scandal based on bribes paid by construction companies to public officials in exchange for lucrative government contracts, many with the state-owned oil company. Last July, Lula was sentenced to more than nine years in prison for allegedly taking bribes worth over $1 million, mostly in the form of a newly refurbished beachfront apartment, from a construction company in return for public contracts.

The conviction amounted to a hard fall from grace for Lula, once the most popular president in Brazil's history. He was the nation's first leader from a poor background — a factory worker who made his way into politics by way of prominent labor unions. Under his leadership, Brazil's economy boomed, and 40 million people rose out of poverty as he built an ambitious social safety net called "zero hunger." 

Yet Lula is currently accused of seven other crimes — including other counts of corruption, influence peddling and illegal campaign financing. In addition to the beach apartment, prosecutors say he received an apartment on the outskirts of Sao Paulo and the $4 million plot of land where his charitable institute is located. 

Lula and political allies deny the charges, maintaining that they are politically motivated. Lula's defense team says he and his wife, Marisa, never owned the beachfront apartment that was the basis of his conviction and Wednesday's appeal; it says they only visited it to consider purchasing it. 

"This process has been marked by gross violations of due process," one of Lula's lawyers, Cristiano Zanin Martins, said this week. "The prosecutors have utilized the press and social networks to try to demonize Lula and try to impede his right to be innocent until proven guilty." he added.

If Wednesday's verdict goes against Lula, his legal team will have at least two more appeals left. Thus far, Brazil's high courts have largely upheld corruption convictions. Nevertheless, his Workers' Party has vowed to keep Lula on the ballot no matter how the ruling goes.

That could present an opening for the right — including far-right firebrand Jair Bolsonaro or Sao Paulo Mayor João Doria, a businessman turned host of Brazil's version of "The Apprentice," who has been widely compared to President Trump. 

Clearing Lula could also risk angering millions of Brazilians who, regardless of their political bent, may see such a verdict as evidence that the powerful in Brazil still have a way to evade justice.

"It would be a moral failure for Brazil if someone who committed so many crimes could be a candidate," said Iria Cabrera, an organizer of anti-Lula protests in Porto Alegre, where the trial will be held.

Faiola reported from Miami.