Mexico Cartels 2026: El Mencho's Death, Sinaloa's Splinter War and US Pressure

WHAT CHANGED SINCE APRIL

The April edition of this briefing described Mexican cartels as "hybrid" armed actors and the issue as a binational security concern. Both remain true, but the politics of 2026 have been shaped by one factor above all: pressure from Washington. The Trump administration designated major cartels as foreign terrorist organisations in 2025, struck alleged drug boats in the Caribbean and Pacific from September 2025 and captured Venezuela's Nicolás Maduro in January 2026. Days later, President Trump said US forces would "start now hitting land" against cartels in Mexico.

Mexico's response has been to escalate its own operations and cooperate closely on intelligence, while rejecting any foreign military action on its territory. The results are visible: the most important cartel leader killed in a decade, dozens of senior traffickers sent to the United States, and a sharp reported fall in homicides. The costs are also visible, in retaliatory violence, fragmentation of criminal groups and political damage within the ruling party.

TIMELINE: 2024 TO SEPTEMBER 2026

• July–September 2024: Sinaloa cartel co-founder Ismael "El Mayo" Zambada is taken to the United States, and war breaks out between the "Chapitos" faction of Joaquín Guzmán's sons and the "Mayos". Culiacán becomes the centre of the fighting.
• 2025: The US designates the Sinaloa cartel, the Jalisco New Generation Cartel (CJNG) and other groups as foreign terrorist organisations. Mexico transfers 55 cartel suspects to the United States in two operations, including Rafael Caro Quintero. From September the US strikes alleged drug boats.
• 9 January 2026: Trump says US forces will "start now hitting land" in Mexico. Sheinbaum repeats that Mexico does "not accept an intervention by any foreign government".
• 20 January: Mexico sends another 37 suspects to the United States, bringing the total to 92.
• 22 February: Mexican special forces kill CJNG leader Nemesio Oseguera Cervantes, "El Mencho", in Tapalpa, Jalisco, using US intelligence. The CJNG responds with about 252 roadblocks in 20 states, arson attacks and assaults on security forces; 25 National Guard members are killed.
• Early May: US prosecutors in New York unseal an indictment accusing Sinaloa Governor Rubén Rocha Moya and nine other current and former officials of protecting the Sinaloa cartel. Rocha takes leave.
• 11 June – July: Mexico co-hosts the FIFA World Cup, deploying about 100,000 security personnel to Mexico City, Guadalajara and Monterrey. The Mexican leg ends without major security incidents.
• June: Official data show an average of 45.4 homicides a day, the lowest for any June in 12 years.
• 22–23 August: Rocha Moya returns to office and, after protests from his own Morena party, requests indefinite leave again the next day.
• Late August: The US military uses a laser weapon to shoot down three cartel drones near the border in Texas's Rio Grande Valley.

THE KILLING OF EL MENCHO AND ITS AFTERMATH

The operation in Tapalpa on 22 February was Mexico's most significant blow against a cartel leader since the recapture of Joaquín "El Chapo" Guzmán in 2016. Mexican special forces, the army and the National Guard raided a property where Oseguera was staying. He was wounded in a firefight and died during evacuation. The US Joint Interagency Task Force–Counter Cartel provided intelligence for the planning. Three soldiers were killed in the raid.

The retaliation was immediate. The CJNG set up about 252 roadblocks with burning vehicles across 20 states, 65 of them in Jalisco, and attacked petrol stations, banks and National Guard facilities. Twenty-three inmates escaped from a prison near Puerto Vallarta, the Guadalajara public transport system shut down and flights were cancelled. By one count 25 National Guard members and about 30 suspected cartel members died in the wave of violence. Jalisco declared a "code red".

The question now is succession. Oseguera's son is in US custody. Mexican and US authorities have named Juan Carlos Valencia González, "El 03", his stepson, as the most likely new leader. The history of Mexican cartels suggests that removing a leader tends to cause splits and new conflicts, not a lasting fall in violence. The CJNG's size and national reach make this especially important to watch.

SINALOA: A WAR OF SPLINTERS

The war between the Chapitos and the Mayos has now lasted two years. The International Crisis Group calls it "Sinaloa's war of the splinters". The army has reduced the worst violence in Culiacán, the state capital, but fighting has moved to rural areas, and killings and disappearances continue. Both factions have fragmented further, and local cells operate with growing independence.

The US indictment of Governor Rocha Moya has turned the security crisis into a political one. Prosecutors accuse him and nine others of taking bribes to protect cartel operations. He denies the charges, remains free in Mexico and has not been extradited. His attempt to return to office in August failed within a day after members of Sheinbaum's own party objected. The case is a test of Mexico's willingness to act against senior politicians accused by the United States.

THE NUMBERS: FEWER HOMICIDES, BUT CAUTION

According to Mexico's National Public Security System, homicides in the first half of 2026 were 30.1% lower than in the same period of 2025, and fell in all but three states. The government says the daily average in June was 45.4, down 48% from September 2024, when Sheinbaum took office. The administration also reports 39,000 arrests, 20,000 guns seized and 1,760 drug laboratories dismantled in its first 14 months.

Analysts have urged caution. Independent researchers note that official homicide figures can be affected by how deaths are classified, and that disappearances, which remain very high, may hide some killings. The Institute for Economics and Peace's Mexico Peace Index 2026 also points to a rise in incarceration as part of the picture. Even so, most observers accept that lethal violence has fallen in several major states.

THE UNITED STATES: PRESSURE WITHOUT INVASION

No US strike on Mexican territory has been confirmed. US pressure has taken other forms. The foreign terrorist organisation designations allow the US to treat cartel support as a terrorism offence. The Trump administration has described the US as being in an "armed conflict" with cartels, has expanded drone surveillance over Mexico and has struck alleged drug boats at sea. In late August the US military shot down three cartel drones near the Texas border with a laser, without saying whether they were over US or Mexican airspace.

Sheinbaum has said that unilateral US military action would be a grave violation of Mexican sovereignty, and that cooperation must be based on intelligence-sharing and respect for each country's territory. The border is also affected by trade tensions and by US migration policy, which has sharply reduced crossings since 2025. Remittances and trade tie the two economies together, which limits how far either side can push.

HOW THE CARTELS ARE CHANGING

Cartel activity has continued to shift beyond drug trafficking. Groups extort farmers and businesses, extort avocado and lime producers in Michoacán, steal fuel and run illegal mining and migrant smuggling. Drones have become a standard weapon: cartels use commercial drones to drop explosives on rivals and communities in Michoacán and Guerrero. CNN reported in July that a Mexican village faced repeated drone attacks during the World Cup, in an area left with fewer security forces while troops were sent to host cities.

Fentanyl remains the central issue for Washington. Mexican cartels, especially the Sinaloa factions, produce much of the fentanyl sold in the United States from precursor chemicals imported largely from Asia. Sheinbaum has countered US demands by pointing to US drug demand and to the flow of US weapons into Mexico, which supplies most cartel firearms.

OUTLOOK: WHAT TO WATCH

• CJNG succession. A contested succession could cause a new wave of violence in Jalisco, Michoacán and Guanajuato.
• A US strike. Any US kinetic action on Mexican soil, with or without consent, would transform the relationship and could trigger cartel retaliation against US targets.
• The Rocha Moya case. An arrest or extradition would signal a new willingness to act against politicians; continued impunity would add to US pressure.
• Homicide trends. Whether the 2026 decline holds after the World Cup deployments end will show how much of it is structural.
• Trade and the USMCA review. Security and trade are increasingly linked in US policy towards Mexico.

Mexico's security picture in 2026 is better on the headline numbers and worse on the risks. Violence is down, but the state's success has come under the threat of US intervention, and the removal of leaders has created openings for new conflicts.

FREQUENTLY ASKED QUESTIONS

What is happening with Mexican cartels in 2026?

Mexico killed Jalisco cartel leader "El Mencho" in February 2026, prompting retaliation across 20 states. The Sinaloa cartel's internal war continues. Official homicide figures fell by about 30% in the first half of the year, and the government has sent 92 cartel suspects to the United States since 2025.

How was El Mencho killed?

Nemesio Oseguera Cervantes, leader of the Jalisco New Generation Cartel, was wounded in a firefight with Mexican special forces in Tapalpa, Jalisco, on 22 February 2026 and died during evacuation. The operation used US intelligence. The cartel responded with about 252 roadblocks across 20 states.

Has the US attacked cartels inside Mexico?

No US strike on Mexican territory has been confirmed. President Trump said in January 2026 that US forces would "start now hitting land". The US conducts drone surveillance, has struck alleged drug boats at sea and in August shot down three cartel drones near the border. Mexico rejects any foreign intervention.

Are homicides falling in Mexico?

According to official data, homicides in the first half of 2026 were 30.1% lower than a year earlier, and June averaged 45.4 a day, the lowest for any June in 12 years. Analysts caution that classification and disappearances may affect the figures.

What is the Sinaloa cartel war?

Since September 2024 the Chapitos, led by sons of Joaquín "El Chapo" Guzmán, and the Mayos, loyal to Ismael "El Mayo" Zambada, have fought for control of the Sinaloa cartel after Zambada was taken to the United States. The fighting has moved from Culiacán to rural areas.

Why did the governor of Sinaloa step down?

In May 2026 US prosecutors indicted Governor Rubén Rocha Moya and nine others on charges of protecting the Sinaloa cartel. He took leave, returned in August and requested indefinite leave again a day later after protests from his own party. He denies the charges.

Was the World Cup in Mexico safe?

Mexico deployed about 100,000 security personnel to Mexico City, Guadalajara and Monterrey, and the Mexican leg of the 2026 World Cup ended without major security incidents. Some rural areas reported increased cartel attacks while forces were concentrated in host cities.

Which cartels are the most powerful in Mexico?

The Sinaloa cartel, now split into rival factions, and the Jalisco New Generation Cartel remain the largest. Both have been designated foreign terrorist organisations by the United States, along with several regional groups.

AUTHOR

SOURCES AND REFERENCES

• TIME – What to know about the operation to kill Mexican drug lord 'El Mencho'
• 2026 Jalisco operation – overview and aftermath
• Lawfare – US-Mexico cooperation after El Mencho
• International Crisis Group – Sinaloa's War of the Splinters
• CNN – Governor of Mexico's Sinaloa state steps down after US drug indictment
• Washington Post – Mexican governor indicted by the US seeks leave again
• US Department of Justice – 37 Mexican nationals transferred to the United States
• Mexico News Daily – Mexico's homicide rate data
• Institute for Economics and Peace – Mexico Peace Index 2026
• CBS News – US military uses laser to shoot down three cartel drones at the border
• CNN – A Mexican village warned of a cartel offensive during the World Cup