Last September, as we reported on this site a while back, two top members of Brazilian president Dilma Rousseff’s posse were sentenced to long prison terms. João Vaccari Neto, treasurer of the ruling Workers’ Party, got more than 15 years for corruption and money-laundering; another party hack, Renato Duque, got 20 years for inflating oil contracts and shoveling the excess profits into the party’s coffers. The convictions of these two men were only part of a large-scale disaster – a blend of scandal and economic crisis – that sent Rousseff’s popularity ratings south, making her, in the words of the Financial Times, “Brazil’s most unpopular president in recent democratic history.”

Then, on February 23, just as Rousseff’s numbers were starting to recover and she seemed to be emerging from under the cloud of possible impeachment, yet another member of her inner circle was put under arrest. Joao Santana, a journalist and political strategist, was the mastermind behind her two election victories and is one of Rousseff’s more intimate friends and advisers – the James Carville to her Bill Clinton. In addition to engineering her victories, he’s also successfully coordinated campaigns for leftist presidential candidates in the Dominican Republic, Angola, Peru, and – notably – for both Hugo Chávez and Nicolás Maduro in Venezuela.

According to the charges leveled against him, Santana knowingly allowed himself to be paid for his services to the Rousseff campaign with several million dollars in funds illegally diverted from Petrobras, the state oil company that is currently at the center of Brazil’s biggest corruption scandal ever. Santana’s homes and offices were raided by 300-odd officers; his wife was also taken into custody. The arrests reportedly came as a shock to Rousseff’s supporters, who fear that Santana may work out a plea bargain with prosecutors in which he throws Rousseff under the bus.

Even if Santana doesn’t turn state’s evidence, to be sure, the goods the cops have on him may be more than enough to sink Rousseff. If it’s proven that she paid Santana with money pilfered from Petrobras, it could mean the official overturning of her election victory. The Portuguese language has a lovely word for this act of invalidation: cassação. As Americas Quarterly staffer Stephen Kurczy recently explained, impeaching Rousseff would involve action by both houses of Congress – which in early December, in fact, initiated impeachment proceedings, only to see them stall shortly therafter. (The proceedings will supposedly resume soon.) Cassação, by contrast, is a process that only requires a ruling by Brazil’s electoral court, the Tribunal Superior Eleitoral – which, as it happens, is already investigating the funding of Rousseff’s 2014 campaign as part of Operação Lava Jato (“Operation Car Wash”), the probe into corruption at Petrobras. If the court determined that Rousseff and her vice president, Michel Temer, had funded their election campaign with illegal funds, both Rousseff and Temer could be removed from office at once, with Rousseff being temporarily replaced by the Speaker of the House, Eduardo Cunha, until a new election could be arranged.

“We’re on the border of changing eras in Brazil,” political consultant Thiago de Aragão told Kurczy. “Until recently, anyone involved in the PT [the Workers’ Party] was immune. Now people are discovering that it’s not like this. The times are changing.” In fact, they’re changing fast. Only days after Santana’s arrest, another Rousseff intimate suddenly resigned his cabinet position. Tune in tomorrow.