Each passing day seems to bring Luiz Inácio Lula da Silva, arguably Brazil’s most formidable political figure, closer and closer to the status of a fallen icon. Lula’s personal journey from being a poor farmer’s son, a dock worker and a trade unionist, to becoming the president of Latin America’s largest country (a position he held from 2003 to 2010), and now a figure battered in the context of an unprecedented, nationwide corruption scandal centred on the oil giant Petrobras, ranks as a resounding saga. The passions that surround it are no less profound. On Wednesday, street protests broke out in 30 cities across Brazil, with protesters calling for Lula’s imprisonment and for the impeachment of his protege, current president Dilma Rousseff.

How Lula will fare in the coming days will say a lot about how Brazil can come to terms with a legacy of murky dealings across the political spectrum, and how it can overcome its current worrying turmoil. This is a historic moment for a whole nation – but Lula’s fate will likely play a decisive role.

That his image has been tarnished can hardly be disputed. From being an almost mythical figure of the left for having pulled tens of millions out of poverty, Lula has now become a highly polarising figure. It’s true he can still claim a degree of popular support, especially with the activists of his Workers’ party, but beyond those groups, he stands accused of having profited illicitly from the privileges of high office. He is seen by many as ready to play tricks rather than be held accountable for his past activities – a man complicit with, rather than opposing, the establishment that he once made a staple of challenging.

This perception brought crowds on to the streets on Wednesday, after the police had released a tape showing that Lula and Rousseff had apparently conspired to ward off an anti-corruption investigation targeting the former president. Last week, prosecutors had filed charges against Lula, accusing him of money laundering and fraud – which he has denied. The presidency also denied any wrongdoing, yet the recording was widely interpreted as revealing why Rousseff had, just hours earlier, sought to bring in Lula as her chief of staff: to offer him a form of judicial impunity. Thursday brought another twist, when a judge blocked Lula’s appointment, underscoring the suspicion that his return to government was a ploy aimed at shielding him from prosecution.

Brazil’s strife cannot be solely ascribed to Lula’s travails. The crisis has many dimensions, not least because of the very scale of the Petrobras corruption scandal, which has shaken the political scene across partisan lines. Politicians of the left, the right and the centre have all been caught up in it. A nation once seen as a poster child of the emerging global south, to be celebrated as the host of this summer’s Olympic Games, now appears on the verge of breakdown. Its head of state is threatened with impeachment, its government barely struggles on, its economy has fallen into recession, street unrest is growing (an estimated 3 million people demonstrated last Sunday), and a no-holds-barred judiciary appears entrenched in the political battle.

It’s true that questions can be raised about the choices made by Sérgio Moro, the federal judge investigating Lula, just as there can be qualms about how and why the police released an ambiguous, explosive tape. Nor is there much doubt that parts of the right see an opportunity for political gain if Lula and his successor end up cornered by various investigations. Much of the outcome may be decided by the street protesters, as much as by judges. By bringing in Lula, Rousseff seems to have played a last card to save her presidency. But that card also carries risks. On Brazil’s social media, one trending comment recalled how Lula once said: “In Brazil, when a poor man steals, he goes to jail, but when a rich man steals, he becomes a minister.”