MEXICO CITY — One scandal featured the president's wife and a $7 million mansion built by a top government contractor. Another involved the misuse of federal AIDS funds to buy Cartier pens and women's underwear. Then there was the "Master Fraud," in which $400 million flowed between 11 government agencies, eight universities and dozens of phony companies — with half disappearing.

Each of the cases was exposed thanks to Mexico’s freedom of information system, often ranked among the world’s most effective. Created in 2002, it has allowed journalists and researchers to wrest documents from a government long known for opacity.

The system has been “one of the most important democratic advances in Mexico” since the end of one-party rule in 2000, said Roberto Rock, a journalist who lobbied for its creation.

Now, President Andrés Manuel López Obrador wants to rein in the National Institute for Access to Information, or INAI, the independent body that runs the system. He says it’s expensive and has failed to end corruption.

The effort has revealed a deepening split in Mexico over the very nature of its democracy. To a generation of reformers, the freedom of information system represented a milestone in Mexico’s transformation from an authoritarian state. The institute was one of multiple independent agencies formed to organize elections, investigate human rights abuses and otherwise serve as checks on the powerful presidency. They became “the protective layers of our democracy,” wrote Enrique Campos Suárez, a columnist for El Economista newspaper.

López Obrador, a populist with leftist roots, maintains that the transition to democracy has largely been a sham — benefiting a self-serving elite while neglecting the poor.

“All these administrative structures were created to simulate a fight against corruption, to simulate transparency, to simulate that there wouldn’t be impunity,” he told reporters. “It was all a farce.”

The transparency law resembles the U.S. Freedom of Information Act. But Mexico’s system typically moves faster, with authorities generally required to respond to requests within 30 days. And it is administered by an institute that can overrule the government when it denies information.

It’s been a game-changer in a country where authorities long withheld basic information such as homicide figures, earthquake casualties and the central bank’s reserves. Suddenly citizens could find out the number of government employees, their salaries — even the guest list for a Mexican president’s birthday party.

The institute “advanced the idea that information didn’t belong to bureaucrats but to the public,”  said  Rossana  Fuentes-Berain, another figure in the civil society campaign to create the system. Since it got off the ground, the number of information requests has exploded, from about 50,000 to more than 230,000 a year.

Reporters have used the transparency system to uncover some of Mexico’s biggest scandals of the past two decades. In 2014, journalist Carmen Aristegui and her colleagues dug up documents showing that President Enrique Peña Nieto and his wife were using a marble-floored, $7 million mansion built by a contractor close to the government. The president’s approval ratings tumbled. (He said his wife, a telenovela star, was buying the property in installments. But he apologized for the appearance of a conflict of interest.)

Three years later, journalists exposed the “Master Fraud” swindle, in which government money sloshed through universities and into fake companies, only to disappear. A former cabinet minister, Rosario Robles, is now in jail on corruption charges. (She says she’s innocent.)

In addition to helping expose corruption, the freedom of information system has allowed researchers to plumb the depths of Mexico’s human rights crisis.

In 2014, reporter Alejandra Guillén became “obsessed” with the mass graves being unearthed in her home state of Jalisco. Many of the unmarked sites were filled with the remains of people who had disappeared during the drug war.

Guillén peppered local and national government offices with nearly 200 requests for information on such pits. Working with the investigative site Quinto Elemento Lab, she documented nearly 2,000 clandestine graves — more than the federal government’s total. Without Mexico’s freedom of information system, she said, “we couldn’t have done much of the investigation.”

López Obrador, a folksy 67-year-old, argues that Mexico no longer needs a transparency institute. He holds a 7 a.m. news conference nearly every weekday, a talk fest that often lasts two hours.

“If we have permanent communication, and guarantee the right to information, things work out,” he told reporters last month. “Therefore, I’d say, we don’t need this apparatus that costs so much.” The hundreds of millions of dollars budgeted for the INAI and other independent agencies, he said, would be better spent on education, health or social programs.

López Obrador and his supporters have long argued that the institute provides the illusion of transparency to a political system dominated by unscrupulous officials and their wealthy allies in private business. “Notwithstanding its admirable institutional design of transparency, Mexico remains one of the most corrupt countries in the world,” the academic Irma Eréndira Sandoval Ballesteros wrote in the 2018 book “Troubling Transparency.”

She’s now López Obrador’s minister of public administration. The president has proposed moving the freedom of information system into her ministry.

Critics maintain that the attacks on the INAI and the other independent agencies show the authoritarian tendencies of a president who frequently berates the press and the opposition, and rules unquestioned over his own political party, which controls the National Congress.

But columnist Jorge Zepeda Patterson said López Obrador’s goal isn’t so much accumulating power as it is fortifying a presidency weakened in recent years by decentralization.

“He’s trying to give the Mexican government more capacity to intervene in reality, to modify the well-entrenched practices that favor the privileged,” he said. “Right or wrong, that’s his logic.”

The freedom of information system might have been hurt by the very hopes it generated for profound change. While Mexico developed a democratic voting system and a freer press, it still hasn’t reformed a justice system rooted in the authoritarian era. The police and courts remain corrupt and ineffective. Only a tiny percentage of crimes result in jail sentences.

“There is more transparency, but we don’t have a functional mechanism to prompt investigation and criminal prosecution and punishment of the corrupt,” said the political analyst Luis Carlos Ugalde. Journalists expose graft, he said, but in many cases “nothing happens” to the perpetrators. That can lead to a sense that the system isn’t producing results.

Ironically, the independent institutions López Obrador criticizes helped propel him to the presidency. One of them, the National Electoral Institute, established in 1990, cleaned up the system of rampant fraud that had kept opposition candidates from winning office. Meanwhile, journalists using freedom of information requests made citizens more aware of corruption. López Obrador rode a wave of disgust with graft to an overwhelming victory in 2018.

Critics note that López Obrador’s government has not always distinguished itself in transparency. In 2019, his first full year in office, there were 46 percent more appeals to the INAI by citizens who had been denied information by bureaucrats than in the previous year.

López Obrador has proposed a leaner, faster freedom of information system in which he says the government would respond to requests within 72 hours. Whether he can succeed in dismantling the current structure is unclear.

The freedom of information system was enshrined in the constitution in 2013 as an autonomous body. To amend the constitution, López Obrador would have to battle the opposition — not only in the National Congress, but in every state legislature.

Rock said the president had the political conviction to push for the change. “But he also has the political savvy to realize it could wind up as a disaster for him and his party,” he said.