Former Brazilian president Luiz Inácio Lula da Silva attends a rally of Brazilian leftist parties in Rio de Janeiro on April 2, days before he began serving a 12-year sentence for corruption. (Mauro Pimentel/AFP/Getty Images)

In the four years since it was launched, a Brazilian anti-corruption probe dubbed Operation Car Wash has ensnared top officials across Latin America, inspiring emulation from Brazil’s neighbors even as it has provoked a backlash from some nervous politicians.

Among its latest victims: popular former Brazilian president Luiz Inácio Lula da Silva, who was jailed for corruption this month in a prison he opened when he held office from 2003 to 2011. Lula, as he is known, was sentenced to 12 years. He denies any wrongdoing.

For many Brazilians, long used to seeing the rich and powerful get away with graft, Lula’s imprisonment feels like a turning point. But it has also raised questions about whether a sweeping corruption probe that has enmeshed much of the country’s ruling class amounts to a momentary crackdown — or heralds a sustainable shift in how Latin America governs and does business.

To be durable, the anti-corruption crusade in Brazil and other affected countries requires structural changes that have yet to be implemented, experts said.

“We had a past of great impunity in terms of corruption, and this vicious cycle has been broken,” said Sérgio Moro, the judge who sentenced Lula and is presiding over the majority of cases in Brazil’s corruption probe.

In March, a demonstrator shows a doll depicting Luiz Inácio Lula da Silva in jail during a protest against the former Brazilian president in front of a Brazilian federal appeals court in Porto Alegre, Brazil.

In an interview, Moro, who has become the hero of the anti-corruption movement for taking on Brazil’s most powerful, added a caveat.

“It is important that cases be judged, that the people responsible be punished according to their trials,” he said, “but there needs to be broader reforms for a definitive victory.”

The anti-corruption investigation has implicated leaders and officials from Mexico to Argentina, along with many in Brazil’s political and economic ruling class. Through Operation Car Wash, prosecutors uncovered a corruption scheme in which Brazil’s largest construction companies paid bribes in exchange for government contracts around the world.

Lula is the latest politician to fall thanks to the Car Wash probe. Brazilian construction company Odebrecht admitted paying nearly $800 million in bribes to leaders in a dozen countries across the region since 2001 in exchange for public contracts.

Last month, Peruvian President Pedro Pablo Kuczynski resigned after his company was accused of receiving bribes from Odebrecht. Kuczynski is the third Peruvian president to be accused in the probe.

Supporters of Luiz Inácio Lula da Silva protest his sentence, in Brasilia, on April 17. (Joédson Alves/EPA-EFE/Shutterstock)

This month, Argentina’s former planning minister was charged with wrongdoing in the awarding of multimillion-dollar contracts to Odebrecht. The scandal has also resulted in prison sentences for two sons of a former president of Panama and the vice president of Ecuador.

As Brazil’s judiciary cracks down on corruption, the Car Wash investigation, once a shameful symbol of the country’s widespread corruption, is turning into a badge of progress, some political analysts say.

“When you look at it from the outside, Brazil is a cradle of corruption. It’s in its bones. But the results of the Car Wash probe have been very positive in strengthening institutions and proving that Brazil is a country that takes care of its own problems,” said Marcos Troyjo, director of the BRICLab at Columbia University, which studies Brazil, Russia, India and China. “It is important to consider the Car Wash investigation as a powerful soft-power tool.”

As the investigation spreads beyond Brazil’s borders, its neighbors are seeking to emulate its anti-corruption efforts. Plea-bargain testimony has been instrumental in tracing the corruption scheme in Brazil. In 2016, Argentina approved legislation that instituted plea bargains for corruption cases. Anti-corruption measures in Latin America have more than doubled since 2001, according to an Inter-American Dialogue study.

These burgeoning anti-corruption efforts have provoked backlash from leaders from Mexico to Guatemala. But politicians are taking note of a growing intolerance for the corruption that was endemic in the region a decade ago. Thousands of protesters have marched in the Dominican Republic, Honduras and Guatemala in recent years to call for an end to corruption. The official theme of last week’s Summit of the Americas in Peru, the country hardest hit by the Car Wash probe outside Brazil, was the region’s fight against corruption.

This is not the first time that Moro or the Brazilian judiciary has attempted to tackle corruption. But the hallmark of the Lula years, Brazil’s swelling middle class, may be responsible for Operation Car Wash’s unparalleled success.

As Brazil’s democracy has matured, its population has grown more educated, connected and demanding, providing the popular support that has served as the investigation’s backbone, according to a report published this month by the Council of the Americas. A whopping 93 percent of Brazilians support the Car Wash investigation, according to an Ipsos poll released this week.

Yet widespread support for Car Wash, which started as a money laundering investigation, has pitted much of Brazil’s electorate against its embattled politicians. Last year, Brazilian congressmen from across the political spectrum voted to block a corruption trial for President Michel Temer. He was accused of receiving $150,000 from a wealthy meatpacking executive — part of a $12 million bribe he allegedly accepted through an aide. At the time, 80 percent of Brazilians favored sending him to trial.

In 2016, legislators defanged an anti-corruption bill that would have provided protections for whistleblowers and cracked down on illegal campaign financing. Instead, they pushed through a law that makes it easier to prosecute judges for overreach.

With 40 percent of Brazil’s Congress under scrutiny for suspected corruption, many officials are desperate to stamp out the probe.

Faced with growing pressure from the country’s jittery politicians in the wake of Lula’s arrest, Brazil’s judiciary is considering a ruling that would allow defendants to avoid prison until they have exhausted all appeals. The decision could help the wealthy skirt jail sentences while their appeals plod through Brazil’s judiciary for decades, analysts said.

Current laws also make it harder for the Car Wash investigation to reach certain groups. A law known as the privileged forum allows currently active public officials to be tried by courts seen as more lenient. Analysts say it has further shielded Brazil’s ruling class from the crackdown that has netted former politicians such as Lula.

“The privileged forum divides Brazilians into two types of citizens,” said Carlos Melo, a professor of political science at the Insper Institute of Education and Research in Sao Paulo. “The anti-corruption process has its merits, but these fragilities need to be addressed, and there needs to be institutional change.”

As the country hurtles toward a presidential election in October, candidates face growing pressure to implement these structural reforms.

Marina Silva, one of the leading contenders in the race and a former cabinet member under Lula, has called for the investigation of Temer and an end to the privileged forum.

Lula’s arrest, she said “is another sign that we can begin to have hope that everyone will be equal under the law, if and only if we continue this process.”