Brazil’s appellate court rejected leftist Brazilian president and current presidential frontrunner Luiz Inácio Lula da Silva’s habeas corpus request on Tuesday that would have kept him from prison until he exhausted his final appeal on a 12-year corruption sentence handed down last year.

Originally sentenced to nine and a half years in prison on money laundering and corruption charges involving the purchase of a luxury property—part of a larger investigation in the government-wide corruption scheme known as “Operation Car Wash”—appellate judges extended his sentence to 12 years in January. Lula retains a final appeal in the lower courts to overturn his sentence.

Brazil’s “clean slate” law prevents anyone convicted on appeal of a crime from running for office, therefore disqualifying Lula from the presidency unless a final appellate process results in the overturning of his sentence. The latest national polls indicate that he is a significant favorite to win the presidency if he legally appears on the ballot.

Lula beginning his prison sentence before this year’s presidential election would prove devastating for his leftist Workers’ Party (PT), which would be forced to campaign for Lula not just in his absence, but against the footage of the former president being processed and placed in prison.

According to Brazil’s O Globo, the Superior Court of Justice voted unanimously against Lula’s request for a habeas corpus petition to prevent him from having to serve any time in prison, despite being convicted, until he exhausted all final appeals. Instead, the court found that he may begin to serve his sentence if his appeals at the lower level fail. The court had ruled in 2016 on this specific issue, finding that forcing convicts to begin their prison sentences before all their appellate options were exhausted did not violate their presumption of innocence, as they had been convicted of a crime. They must only exhaust their lower court options.

Folha de Sao Paulo suggests that challenging the 2016 decision may be the next step for Lula’s legal team. The process may give Lula six months to a year, enough time to run a presidential campaign.

The case now kicks back to the lower court, the same court that expanded his sentence to 12 years. “If the regional court rejects Lula’s appeal of the sentence, he would be liable to go to prison even pending further appeals before higher courts,” Agence France-Presse (AFP) notes.

The case remains under appeal and is scheduled to continue on March 23, when presiding Judge Victor Laus returns from vacation. The Brazilian magazine Veja reports that sources suggest the court will request Lula’s arrest this month.

Police have prepared for the possibility of street violence in the event Lula is arrested. “About 350 people will be on standby and the Military Police are on alert to contain protests and isolate avenues considered strategic for the logistics of the operation,” Veja adds.

On Tuesday, Lula called judges who rejected the request “torturers” and insisted that he would not flee the country. Lula’s attorney, Sepúlveda Pertence, told reporters the decision to reject his request was indicative of a “punitive attitude en vogue in the country” and lamented that the court “missed a chance to evolve and return the constitutional guarantee of presumption of innocence its proper worth.“

Despite the ongoing legal drama, voters continue to prefer Lula over other candidates, including the conservative lawmaker Jair Bolsonaro and impeached ex-president Fernando Collor de Mello. A poll released Tuesday found that 33.4 percent of voters would prefer Lula to other candidates, inexplicably up from September despite the extension of his sentence to 12 years, and would defeat both of the likeliest run-off candidates, Bolsonaro and leftist Marina Silva. Brazil’s election law requires a run-off election if no candidate receives 50 percent of the vote.

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