New Challenges, Old Playbook: The U.S.-Mexico Drug War Partnership

Washington, D.C., April 29, 2026 - The reported deaths last week of two CIA officials in northern Mexico after an operation to dismantle a clandestine drug lab have heightened tensions between the two countries over the extent of U.S. government involvement in Mexican security operations. First identified as U.S. Embassy personnel, media reports have since revealed that the Americans who died alongside two Mexican officials in a car crash in the state of Chihuahua on April 19 worked for the Central Intelligence Agency. President Claudia Sheinbaum said that her security cabinet was not aware of any “direct work or coordination” between the state of Chihuahua and U.S. Embassy personnel and that she had demanded an explanation from the Trump administration and the government of Chihuahua. As of now, there are conflicting reports about the role of the U.S. officials in the operation and what exactly Mexico’s federal government knew.

As the story continues to develop, the National Security Archive today publishes a set of declassified U.S. records on the Northern Border Response Force (NBRF), a joint U.S.-Mexico program initiated in 1990 that was one of the first major commitments of U.S. personnel and intelligence to combat narcotics trafficking in northern Mexico and that established a model for cooperation (the sharing of U.S. intelligence with U.S.-trained Mexican security forces) that has endured for more than 35 years.

These documents offer a window into an era of rapidly increasing U.S. involvement in counternarcotics operations at a time when Mexico had become one of the most important transit zones for illegal drugs entering the United States. They also provide insight into several persistent themes and obstacles in U.S.-Mexico security cooperation, spotlighting issues that continue to complicate the bigger and more ambitious anti-narcotics programs that define U.S.-Mexico security cooperation today. These include Mexico’s sensitivity to perceived infringements of its sovereignty; the apparent ease with which criminal groups have been able to adapt to new enforcement strategies; U.S. concerns about high-level corruption in Mexico, especially in the army; and the inherent difficulties in defining and measuring success in a militarized counternarcotics strategy.

Designed to “eliminate the use of northern Mexico as a staging area for cocaine shipments,” NBRF relied on U.S. training and radar installations to help Mexico “detect drug-laden smuggling aircraft, interdict the aircraft as they land in Mexico, arrest traffickers, seize aircraft and narcotics, and conduct follow-up investigations to collect evidence that can be used to dismantle trafficking groups.” The program was one of a several major new international counternarcotics interdiction programs that took shape as the Cold War wound down during the administration of President George H. W. Bush.

U.S. support to NBRF was coordinated through the U.S. Embassy in Mexico City and involved personnel from the Department of State, the Department of Defense, the Drug Enforcement Administration (DEA), and the U.S. Customs Service, which tracked suspected drug trafficking aircraft while in the air. DEA was the only agency that was authorized to accompany their Mexican counterparts on the ground in NBRF field operations, a practice that “was ended early in the program due to DEA safety concerns.”

On the Mexican side, the Attorney General’s Office (Procuraduría General de la República, PGR) was the lead agency on the task force, while interdiction was the exclusive responsibility of the Federal Judicial Police (Policía Judicial Federal, PJF). The Mexican Air Force and the Mexican Navy also participated in the program.

The Mexican government conducted a pilot program for the Northern Border Response Force between April and July 1990. Agents initially seized a significant amount of cocaine and trafficking assets, largely due to the novelty of interdicting aircraft transiting Mexico. However, a joint U.S. interagency assessment of the NBRF produced the following year acknowledged that “the flow of cocaine to the United States has continued at high levels” due to traffickers quickly changing tactics and smuggling routes. (Document 8) Despite the program’s documented inefficiencies, U.S. officials continued to herald the NBRF as an “important national security endeavor” and considered the Mexican government to be a “dependable partner in the anti-drug effort.” (Document 7)

As the two countries ramped up counternarcotics efforts through the NBRF, an event at the end of the year would throw this close collaboration into jeopardy. On November 7, 1991, Mexican army troops attacked and killed seven Federal Judicial Police agents who formed part of a NBRF unit during a counterdrug mission in Veracruz. The incident led to the firing of a top army general and the launch of a corruption probe into the Mexican military’s protection of drug traffickers. DEA Administrator Robert Bonner called the Veracruz killings a “critical watershed event” for the Mexican government “regarding its commitment to the counter-narcotics effort and its resolve to root out corrupt officials, even Army Generals, that collude with traffickers.” (Document 9) Months later, the U.S. Embassy in Mexico City assessed the deteriorating security relationship, acknowledging that the presence of U.S. Customs aircraft on the scene during the army’s attack on the NBRF agents had renewed “Mexican sensitivities about U.S. involvement in anti-narcotics activities” in the country. The Embassy clarified that the “nationalist reactions” provoked by the deployment of the Customs planes in Mexican territory did not consider that this action was authorized and “carefully and closely coordinated” with the Mexican government. (Document 10)

Despite the challenges that faced the program, lawmakers determined the NBRF’s methodology to be sound and pushed for further cooperation efforts that followed the same model of sharing U.S. intelligence while training and equipping the Mexican security agencies that would act on it. By the late 1990s, Mexico’s federal government had increased its budget for purchasing counternarcotics and law enforcement equipment and had enhanced coordination efforts with the U.S. A senior Mexican government official termed the new initiative “a total war against the scourge of drugs.”

Reports of increased CIA involvement in Mexico are evidence of a much more aggressive counternarcotics policy during the second Trump administration, but the history of NBRF is a reminder that the Trump counternarcotics surge follows a playbook written years before. While the stakes appear higher than ever, much can be learned from looking back at past cooperation. It may be a new era of policy, posturing, and challenges, but the historical record suggests little has changed.

The records featured below, including several documents from the recently published Digital National Security Archive collection, Mexico-United States Counternarcotics Policy, 1969-2013, were obtained by the National Security Archive under the Freedom of Information Act (FOIA).