The demise of one of Mexico’s most notorious cartel leaders in a military operation on Sunday has triggered a wave of violent retribution across the nation.

Reports indicate that over 50 individuals lost their lives, 252 roads were obstructed with burning vehicles, and the ensuing chaos led to numerous flight cancellations at the airports in Puerto Vallarta and Guadalajara.

This upheaval follows the death of Nemesio “El Mencho” Oseguera, the leader of the Jalisco New Generation Cartel (CJNG), highlighting a new phase in the Mexican government’s campaign against drug cartels.

In the aftermath of El Mencho’s death, the CJNG declared hostilities against the socialist government of President Claudia Sheinbaum, effectively paralyzing Guadalajara, Mexico’s second-largest city.

“The current situation is a direct response from his followers,” stated Robert Almonte, a Texas-based security expert and former deputy chief of the El Paso Police Department with a focus on narcotics.

“Their loyalty to him is unwavering. They were willing to sacrifice their lives for him. This violence represents a strike against the Mexican authorities, who have initiated a renewed offensive against the cartels in collaboration with the US. It also signifies an escalation in the US’s efforts to dismantle these drug organizations,” he explained to The Post.

More than 25 of those killed Sunday were Mexican National Guard troops, as narco gangs went on a rampage, torching buildings and cars. US tourists in nearby Puerto Vallarata were warned to shelter in place, until flights were restored Monday.   

There were fears US citizens in Mexico could be targeted after the country’s Ministry of Defense confirmed the US provided intelligence and other unspecified support in the military operation resulting in the death of Oseguera in the mountains of Jalisco, from where he had run his drug operation for decades.

Sheinbaum made clear Monday there was no US involvement on the ground in Mexico during the raid, but that security and intelligence sharing has increased.

“All operations, from their planning onwards, are the responsibility of the Mexican federal forces,” Sheinbaum clarified.

The president is taking a different approach to her predecessor, Andres Manuel Lopez Obrador, who had been accused of protecting members of the Sinaloa cartel, another narco-trafficking operation, for years, even though they represent the same Morena political party.

According to a Drug Enforcement Administration (DEA) report, Obrador received millions of dollars from Sinaloa leader Joaquin “El Chapo” Guzman for his unsuccessful 2006 campaign for president.

The former Mexican leader also adopted a controversial “abrazos, no balazos” — hugs not bullets — campaign, focusing on the socio-economic reasons for drug trafficking. He once also blamed US families for the fentanyl crisis, claiming they they didn’t hug their children enough.

“[Obrador] was protecting the Sinaloa cartel because he was in on it,” claimed Almonte.

He added it was his presidential predecessor, Enrique Pena Neto, who had asked for the US to help capture and extradite notorious kingpin El Chapo, who was convicted of murder and drug trafficking in a Brooklyn federal court in 2019 and is currently serving a life sentence in a maximum security prison in Colorado.

CJNG was originally an offshoot of the Sinaloa cartel, formed sometime between 2007 and 2009 by Oseguera — an ex-police officer – his brother, and others.

Under his direction, CJNG had become more ruthless and savage than the already bloodthirsty and ultraviolent cartels.

In 2015 Oseguera and his men brought down a military helicopter with rocket propelled grenades, killing nine people. They strapped dynamite to enemies’ bodies so they exploded while they were still alive and they routinely displayed the decapitated and tortured corpses of rival drug traffickers in town squares as a warning.

In 2024, Mexican authorities found the bodies of five decapitated men on a road in western Jalisco state. The bodies were found in black plastic bags, according to the state prosecutor’s office. Nearby, authorities found another bag containing the heads of the victims.

CJNG is also known to have used landmines and explosives-laden drones to kill other gang members, cops and soldiers. The gang is also working with Middle Eastern jihadi “technical advisers,” according to Mexican law enforcement and security sources.

In 2015, the cartel targeted Mexican law enforcement, killing 15 police officers in an ambush on a convoy.

Sunday’s mission was directed by Omar Garcia Harfuch, Mexico’s Secretary of Security, who had narrowly survived his own assassination attempt by CJNG six years ago.

He was attacked in Lomas de Chapultepec, one of the wealthiest “colonias” in capital Mexico City. Such areas are where both high-powered government, civil officials and narco bosses all live, generally considered to be off-limits due to a “pacto de narco” — an agreement not to attack.

At the time of the ambush, which left him with three bullet wounds and two police officers dead, Harfuch, 44, vowed to crack down on narco terrorists.

In 2024, Sheinbaum appointed him Secretary of Security and Civilian Protection, a key position in her presidential cabinet.

Garcia Harfuch has also received training from the DEA and the FBI, and is said to be completely on board with President Trump’s goal to end the trafficking of fentanyl into the US.

After Trump designated cartels as terrorist organizations last year, Garcia Harfuch sent 29 suspected cartel leaders to face justice in the US.

Weeks before El Mencho’s death, Harfuch — who began his career in federal police intelligence — was instrumental in capturing Ryan Wedding, the Canadian former Olympic snowboarder allegedly working for the Sinaloa cartel, who was on the FBI’s 10 most wanted list.

Oseguera commanded a $15 million bounty from the US, in part related to his group’s trafficking in fentanyl, cocaine and other drugs.

For Sunday’s operation, security forces tracked one of his girlfriends to Tapalpa, a secluded resort town in the pine forest-covered mountains in Jalisco’s southwest, Mexican authorities said during Sheinbaum’s daily press conference Monday.

Following El Mencho’s death, the CJNG cartel is likely to be led by one of El Mencho’s family members, according to Almonte.

The leadership could go to Juan Carlos “Numero 3” Valencia Gonzalez, his son-in-law. El Mencho’s older brother, Abraham Oseguera Cervantes, who co-founded the cartel, was captured by Mexican security forces last year.

Oseguera’s son, Ruben “El Menchito” Oseguera Gonzalez was extradited to the US to face drug trafficking charges in 2020.

Other cartel experts say that Oseguera’s wife, Rosalinda Gonzalez Valencia, might also be a possibility to take over. Gonzalez Valencia, know as “La Jefa” or The Boss, is in charge of the cartel’s finances, and was convicted of financial crimes in 2023, but granted early release in February 2025, according to Mexico’s Secretariat of the Interior.

Waves of cartel violence in reaction to a leader’s killing are not unusual. Similar happened when one of El Chapo’s sons was captured in Culiacan, the headquarters of the Sinaloa cartel, in 2023.

The killing of one cartel leader may indicate the Mexican government is serious about tackling cartels, but as history has shown, leaders are quickly replaced.

Numbers for how many people are involved in these secretive gangs across Mexico are tough to estimate, but a study published in Science magazine in 2023 estimated between 160,000 to 185,000 across the country, making them “one of the country’s top employers.”

Experts say the only way to win will be to keep applying force.

“Regardless of who takes over the leadership, it’s important that we continue to keep pressure on the cartel to not let the new leader take over and move it forward,” Almonte said.

“We need to continue hitting them with everything we’ve got.”