Thousands of Brazilians took to the streets of the nation’s largest cities on Tuesday and Wednesday in anticipation of a Supreme Court decision that opened the door for the arrest of socialist presidential frontrunner Luiz Inácio Lula da Silva late Thursday morning.

Brazilians congregated at the headquarters of Lula’s socialist Workers’ Party (PT) and on the streets of Brasilia, among other cities, dressed in red and holding images of their leader. On the right, conservatives and anti-corruption voters congregated wearing the national colors, green and yellow, and brandishing dolls known as pixulecos—figurines of Lula wearing a traditional prison uniform.

The nation’s Supreme Federal Tribunal (STF) took an 11-hour vote on Wednesday, ending shortly past midnight Thursday, on a habeas corpus petition by Lula’s defense team. If granted, Lula—who served as president once before in the mid-2000s—would have been allowed to avoid prison until he exhausted all legal appeals in his case.

Lula da Silva was convicted of corruption and money laundering last year and sentenced to 9.5 years in prison. An appeals court affirmed the conviction and extended the sentence to 12 years. Lula’s attorneys argued that he should not begin that sentence until a third and final appeal occurred.

The STF disagreed by a slim margin. In a 6-5 vote, the justices rejected the habeas corpus petition, allowing the judge that initially convicted him, Sergio Moro, to issue a warrant of Lula’s arrest at any time. The president of the court, Justice Carmen Lúcia, voted against the petition, arguing that similar cases involving much lower-profile defendants had been decided that way.

Despite his conviction—tied to over one million dollars Lula was found to have accepted in bribes as part of a larger corruption scheme—Lula remains the frontrunner in October’s presidential election. A poll released on March 31 by the firm Datafolha found 36 percent of voters intending to vote for Lula, compared to 18 percent for the second most popular candidate, conservative lawmaker and veteran Jair Bolsonaro. No other candidates received over 10 percent of the vote. In a scenario where Lula does not appear on the ballot, Bolsonaro leaders with 20 percent, while environmentalist leftist Marina Silva rises to receive 16 percent of the vote.

On Thursday, Bolsonaro published a video applauding the STF decision. “Brazil scored a goal against impunity and corruption, but just one goal. One enemy is eliminated,” he said, adding that Brazil must elect “a president, man or woman, who is honest … and a patriot.”

Após decisão do STF cabe a cada um de nós se empenhar para mudar o destino da nossa Pátria. https://t.co/eeNOKjt1Nd — Jair M. Bolsonaro (@jairbolsonaro) April 5, 2018

The Brazilian newspaper O Globo reports that there remains a slim chance that Lula appears on the ballot despite his conviction and the existence of Brazil’s “Clean Slate” law, which prohibits any individual convicted of corruption from holding public office. “In theory,” the newspaper notes, Lula can file for a preliminary injunction by August 15 that would freeze that law from having an effect. He is also eligible to register his candidacy with the national electoral commission, though they will likely reject it as he will be serving a prison sentence.

The PT has until 20 days before the October election to find a new candidate if all these tactics fail and keep Lula off the ballot. For now, the party—which previously admitted to having no “plan B” in the event that Lula could not run—is aiming for keeping socialists on the streets and disrupting daily life in cities, pressuring the government to allow Lula in the race or face consistent disruptions.

Folha de Sao Paulo reports that the PT’s plan in the event that Judge Moro issues a warrant is for Lula to visit Sao Bernardo do Campo’s metalworkers’ union, where he is popular, and organize a crowd.

“It is time to put people on the streets, make a great mobilization against fascism and for the defense of democracy,” Senator Lindbergh Farias, the head of the PT in the chamber, said on Thursday.

Supporters of Bolsonaro—and supporters of imprisoning Lula, whether or not they would vote for Bolsonaro—also congregated on Tuesday by the thousands to plea for the STF to reject the habeas corpus petition. As the PT organizes street events, many expect similar responses from the right.