The prosecutor general's office says it will appeal the Supreme Court's decision.
A Brazilian Supreme Court judge on Monday overturned the graft convictions against former president Luiz Inacio Lula da Silva, clearing the way for the left-wing leader to run in the 2022 presidential election.
Justice Edson Fachin overturned both convictions against the popular-but-tarnished ex-president (2003-2010) stemming from a probe into a massive corruption scheme centered on Brazilian state oil company Petrobras.
Fachin ruled the court in the southeastern city of Curitiba that convicted Lula "lacked jurisdiction," and sent four related cases against him – two of which were still pending judgment – to a federal court in the capital, Brasilia.
Lula, 75, regains the right to run for office unless the convictions are reinstated.
The prosecutor general's office said it would appeal.
"This is recognition that we were right throughout this long legal battle," Lula's lawyers said in a statement.
They called the decision vindication of their arguments: "ex-president Lula's innocence, the invalidity of the cases and the 'lawfare' that was waged against him."
READ MORE: Brazil's Lula ordered to prison within hours
The cases stem from Operation Car Wash, a sprawling anti-corruption investigation that brought down a Who's Who of powerful politicians and business executives in Brazil, jailed for using inflated construction contracts to systematically fleece Petrobras for billions of dollars.
Lula, who spent more than 18 months in prison before being freed in 2019 pending appeal, was the most powerful figure felled.
Prosecutors accused him of using the corruption scheme to take bribes, remodel a triplex beach apartment and channel illegal funds to his foundation.
His image was badly tarnished by the convictions, which resulted in jail sentences totaling 26 years.
Still, an Ipec opinion poll published Sunday gave Lula more potential votes in the October 2022 presidential elections than President Jair Bolsonaro – the only politician to outperform the incumbent.
'The show's just starting'
Lula claims he is innocent, and that the cases against him were fabricated to take him out of the running for Brazil's 2018 presidential race.
That election was ultimately won by far-right Bolsonaro, who capitalized on massive backlash against Lula's Workers' Party (PT).
Lula supporters have long cried foul.
They point to the fact that the lead judge in the Car Wash probe, Sergio Moro, went on to accept the post of justice minister under Bolsonaro, and that hacked phone messages show he conspired with prosecutors to ensure Lula was sidelined.
Social media in Brazil erupted with pictures of Lula donning a pair of red sunglasses or tearing into a punching bag with boxing gloves on.
“There is a risk that when the campaign formally begins in June next year, Bolsonaro and Lula are so ahead of their opponents that there is no time for a third candidate”, 👇🏻 https://t.co/cBASfbm5km— thomas traumann (@traumann) March 8, 2021
"The 2022 election started today," opinion columnist Thomas Traumann wrote on Twitter.
"If you thought Brazil was politically polarized before, take a seat, because the show's just getting started."
Lula remains a hero on the left, and many Brazilians fondly recall the economic boom he presided over, as well as social programs that helped lift millions of people from poverty.
"Lula innocent," his party proclaimed on Twitter.
But his vindication is far from complete. The former metal worker-turned-president still faces several other corruption and influence-peddling cases, aside from the Operation Car Wash charges.
And he remains highly controversial – so much so that the Sao Paulo stock exchange plunged by 2.5 percentage points after news of the court decision broke.
The former president's press office said he had no immediate comment on the ruling.