MEXICO CITY — Even in a nation almost inured to corruption, the news was astonishing.
The man considered to be the brains behind the Mexican government’s militarized war on drug traffickers stood accused by American prosecutors of having been in the pocket of one of the major criminal groups he was ostensibly pursuing, severely undermining the very fight he was helping to lead.
Genaro García Luna, Mexico’s former public security secretary, was charged with taking millions of dollars in bribes while in office to protect the Sinaloa Cartel, allowing the organization to smuggle tons of cocaine and other drugs into the United States. At the time, the group was led by Joaquín Guzmán Loera, better known as El Chapo, who is now serving a life sentence in the United States.
The indictment, unsealed in New York on Tuesday, and the subsequent arrest of Mr. García Luna in Dallas hours later, stunned Mexico. It was as if Eliot Ness had actually been an accomplice of Al Capone.
“It’s huge,” said Jaime López-Aranda, a security analyst in Mexico City who briefly worked under Mr. García Luna in the late-2000s. “I’m still a little bit in shock. And I keep thinking back to the guy and our conversations and his team and his people. It’s the sharp disappointment. I mean — my God, man. It’s like — ” He paused. “It’s like the end of an era.”
Mr. García Luna was the chief engineer of the country’s controversial counternarcotics strategy that relied heavily on the armed forces to confront criminal groups and kill or capture their leaders. Mexico is still grappling with the legacy of his approach.
While it had some success in capturing dozens of prominent crime bosses, deploying the military also spurred a sharp increase in violence and left a trail of death, as monolithic criminal enterprises were fragmented into an array of groups that have proven to be even more violent and uncontrollable.
For some Mexicans, the news of Mr. García Luna’s arrest was almost unimaginable. For others, it was proof of enduring suspicions that he had been in bed with criminals all along. Still others interpreted it as a sweeping — and scalding — referendum on the two administrations in which he served.
Then there were those who found confirmation that the whole apparatus of Mexico’s government was once and forever corrupt.
Mr. García Luna was one of the architects — and the embodiment — of Mexico’s security strategy for a decade. From 2001 to 2005, during the administration of President Vicente Fox, Mr. García Luna led the Federal Investigative Agency, Mexico’s equivalent of the F.B.I. He then became the public safety secretary in the cabinet of President Felipe Calderón from 2006 to 2012, overseeing his boss’s “war” on drug trafficking organizations and the deployment of the Mexican military to wage it.
Politically powerful, Mr. García Luna curried intense loyalty among his supporters but also inspired deep animosity among his critics, particularly when violence soared amid Mr. Calderón’s offensive against the traffickers. The strategy disrupted the criminal ecosystem but did not contain the violence between criminal groups, resulting in the deaths of tens of thousands of people and the disappearance of many others.
The strategy continued under President Enrique Peña Nieto, but the current president, Andrés Manuel López Obrador, has sought to discredit it, pointing to the fact that it failed to curb either drug trafficking or violence.
At a news conference on Wednesday, Mr. López Obrador said his government would not use the case of Mr. García Luna to beat up on Mr. Calderón, an outspoken critic of the current president.
“I do not want you to think that we are taking advantage of this circumstance to attack former President Calderón, despite all the damage he did to us, not only to me, but to the country,” Mr. López Obrador said.
But the president couldn’t seem to help himself, moments later describing the arrest as “a defeat to an authoritarian, corrupt regime, an element of proof that this model failed.”
Anabel Hernández, a Mexican investigative journalist who has reported extensively on the alleged ties between Mr. García Luna and drug traffickers, found in his arrest some vindication of her work.
“There was not a war against drugs per se, but rather a war between cartels in which the federal government picked a side and protected the Sinaloa Cartel, which only meant more violence for society and more power to the cartel,” Ms. Hernández said in an interview.
But for her, the indictment and arrest — in a foreign country — also reaffirmed her abiding frustration with the weaknesses of the Mexican state.
“It reflects the immaturity of the Mexican political system, the lack of autonomy and inefficiency of the Mexican justice system,” she said.
Some delighted in the news with a certain schadenfreude. In office, Mr. García Luna was hungry for media attention. Federal agents under his command once staged the arrest of a suspected kidnapper, and the liberation of three hostages, for broadcast on national television. He also enjoyed parading suspects before reporters and posing them with the piles of weapons and drugs impounded during their arrests.
“For poetic justice, I would very much have liked a live television transmission of the detention of García Luna,” Leonardo Núñez González, a political analyst in Mexico City, wrote on Twitter. “But these things only happen in places like Mexico.”
Many close associates of Mr. García Luna have largely kept quiet since the news of his indictment broke, as observers have speculated whether he has information that could lead to further indictments of former officials, not only in Mexico but also in the United States, which worked closely with Mr. García Luna during his years in government.
Some observers were quick to point an accusatory finger at Mr. Calderón, saying that if his chief security minister had been working hand-in-hand with the Sinaloa Cartel, and getting huge payments for his efforts, then the president had to have known.
“This indictment discredits the whole Calderón presidential term for a lot of people,” said Mr. López-Aranda, who served as Mr. García Luna’s spokesman at the Public Security Ministry for less than a year.
For supporters of Mr. López Obrador, he added, “Christmas came early. Christmas for the next five years came early.”
Mr. Calderón, who was not accused of any wrongdoing in the American indictment, said on Twitter: “My posture is always in favor of justice and the law.” But if the charges against Mr. García Luna were true, he wrote, it would be “a serious violation of the confidence entrusted in him.”
Guillermo Valdés, who ran CISEN, a national security intelligence agency, during Mr. Calderón’s term, cautioned that even if Mr. García Luna were to be found guilty of the charges he faces, the entire government should not be implicated.
“This would be a major blow to the Calderón administration, having a corrupt secretary of public security,” he said. But, he continued, “you simply cannot conclude that because of one corrupt government official, the rest of the government were obedient to the corrupt.”
“It will be very sad to realize that you worked with a two-faced official,” he added. “And in that case we will have to admit that it was a monumental mistake to keep him.”