Until a couple of weeks ago, not many Brazilians had heard of Eronildes Vasconcelos. Fellow parishioners in Salvador, her home town in northeast Brazil, know the churchgoing 44-year-old widow and mother of two as a junior member of the country’s growing evangelical Christian congressional caucus.

But thanks to the unlikely role she’s been called on to play in shaping the outcome of Brazil’s widening political corruption scandal, Vasconcelos has become a national celebrity of sorts. Her every hosanna now galvanises public attention from Twitter to the Planalto presidential palace in Brasilia.

Vasconcelos — or Aunt Eron, as she prefers — is no power broker. She just happens to sit on the congressional ethics committee, where she’s wound up with the decisive vote on the fate of one of the country’s most notorious political operators, speaker of the Lower House Eduardo Cunha.

The pressure on Eron offers a screenshot of Brazil at its worst, a land in which national institutions become clay in the hands of clever politicians. Cunha’s staying power is a lesson in how bigshots practiced at raiding public coffers can pull the levers of high office to outrun the law — often with a wink and a nod from aspiring acolytes.

Cunha has been charged with a constellation of offences, from tax evasion to pocketing seven-figure bribes from government suppliers. The Supreme Court ruled that he should stand trial and Brazil’s prosecutor general wants him arrested, but none of that can happen unless Cunha’s peers vote to strip him of parliamentary immunity. And this is where Brazil’s political esprit de corps come into play.

Cunha knows the script. A skilled campaign fundraiser, and a master of the arcana of legislative rules, he has invoked every prerogative and called in every favour to cling to power, even as the allegations piled up against him and street protests turned him into a national pariah.

It was Cunha who marshalled the congressional supermajority in April that authorised impeachment proceedings against President Dilma Rousseff. She has since been suspended from office on charges of budget fraud and will not return if the senate finds her guilty, which is likely. All the better for her stand-in, vice-president Michel Temer, who will serve out her term if she falls.

And yet after seven months of stonewalling and manoeuvres on the ethics committee, Cunha’s time finally may be running out. This week the 21-member committee finally is expected to vote. Ten lawmakers reportedly favour sparing Cunha, while nine publicly want him gone. Aunt Eron has yet to declare her vote. If she joins the rebels and evens the score, the committee chair would step in to cast the deciding vote — and he’s already on record calling for Cunha’s ousting. With her backing, however, Cunha could keep his seat and evade prosecution.

How she’ll vote is anyone’s guess. One of the few black women to be elected to congress, Vasconcelos is a former bible studies teacher — hence her nickname “Aunt”, the affectionate Brazilian moniker for teacher — and served four terms as a city councillor in her hometown Salvador, a regional capital.

She’s also a lifelong member of the Universal Church of the Kingdom of God, a big Pentecostal order in Brazil, and is known for her community service and legislative initiatives supporting women and the disadvantaged. She joined the congressional ethics committee in April, replacing one of Cunha’s adversaries, which led to speculation that she was a Cunha plant. On her committee debut, Vasconcelos lavishly praised the House Speaker, calling congress under his leadership “more productive than ever”. At the same time, she conceded Brazilian politics needed a thorough “cleansing”. Such ambiguity has suddenly made her the most courted public figure in Brasilia, beseeched by political heavies, religious figures and a scrum of media.

As public clamour grew more intense last week, Eron did what any crowd-conscious representative of the people might do under pressure: She hid. On June 7, while ethics committee members clashed over Cunha’s future, Vasconcelos retreated to her office in Brasilia, fuelling whispers of furtive deals in the making and a cascade of internet “Where’s Tia Eron?” memes in the vein of Where’s Wally?

Brazilians may well ask. Thanks to the work of independent-minded police, judges and prosecutors, Brazil has made huge strides in bringing crooked officials to justice. Cunha is just one target in a massive federal corruption case that has seen more than 100 people sentenced to a total of 1,140 years in prison. Convictions for corruption jumped 438 per cent from 2010 to 2015, justice department figures show.

But good jails are no proxy for good government, and little will come of such prosecutorial zeal as long as tainted politicians are able to use elected office as a safe house. It’s a measure of the parlous state of national politics that Cunha’s fortunes could also determine Brazil’s.

The legislature now has a historic chance to correct that aberration. Vasconcelos has claimed she will not shirk her duty, whatever she thinks that may be. She could take her cue from the wider congregation: 77 per cent of Brazilians want Cunha gone, according to a recent poll.

— Bloomberg

Mac Margolis is writer based in Rio de Janeiro.