For decades, US-Mexico law enforcement and counternarcotics cooperation has been fraught with difficulties stemming from a history of strained relations. These challenges date back to the 1980s, most notably marked by the torture and murder of US Drug Enforcement Administration agent Enrique “Kiki” Camarena. This event revealed deep-rooted corruption within the Mexican government and law enforcement. Mexico’s sovereignty concerns and the pervasive infiltration of cartels into its government, military, and law enforcement institutions have continuously hampered efforts at collaboration.
Despite these challenges, US-Mexico security cooperation managed to climb during President Felipe Calderón’s term (2006–2012), highlighted by the launch of the Mérida Initiative in 2007, which provided Mexico with over $1.5 billion in security assistance by 2012. This collaboration led to significant successes in targeting cartel leaders and a significant increase in extraditions to the United States. However, the period also exposed deep challenges within Mexico’s institutions. Violence escalated considerably despite these efforts, with homicides nearly tripling between 2007 and 2011. Concerns about human rights abuses by Mexican security forces grew. And corruption remained a significant issue, exemplified by later revelations about potential cartel ties of high-ranking officials.
The subsequent administration of Enrique Peña Nieto (2012–2018) initially appeared to distance itself from the previous approach to US cooperation. During his first year in office, Peña Nieto seemed to put the Mérida Initiative on hold, requiring all cooperation to go through a “single window” in his administration’s interior secretariat, which delayed the dispersal of millions in assistance. However, as his term progressed, Nieto’s security policies came to resemble those of his predecessor. He continued to work with US intelligence to arrest high-value targets, capturing or killing 109 of the 122 traffickers that the Mexican government considered most dangerous.
Andrés Manuel López Obrador, president from 2018 until September of this year and a traditional leftist with strong nationalist tendencies, further scaled back cooperation to nearly zero. His reluctance to engage closely with the United States stems partly from his close ties with the military, especially after US authorities arrested General Salvador Cienfuegos, a former Mexican defense secretary. Cienfuegos had been indicted by US law enforcement on drug trafficking charges. He was returned to Mexico a month after his arrest, reportedly after an agreement that Mexican authorities would investigate him, but he was swiftly released, highlighting the ongoing tension in the bilateral relationship.
The López Obrador Administration’s Approach
López Obrador’s broader security policy, often referred to as the “hugs not bullets” strategy, marks a significant departure from his predecessors’ approaches to combatting criminal organizations. His administration focused on socioeconomic programs aimed at preventing young people from joining criminal groups rather than directly confronting these organizations through law enforcement. López Obrador believed that if law enforcement pulled back, the cartels would resolve their conflicts internally, reducing violence. However, this approach largely failed. Violence in Mexico has intensified and cartel influence has expanded, increasingly affecting daily life, the economy, and politics. Cartels have become more brazen in their criminal activity, tightening their grip on regions previously untouched by such violence.
One of the most complex issues affecting US-Mexico relations in drug enforcement is migration. Former President Donald Trump’s focus on controlling migration from Mexico gave the Mexican government leverage. President López Obrador has strategically used Mexico’s role in managing migrant flows—referred to as instrumentalized migration—as a bargaining tool. By using migration as leverage, López Obrador has deflected US pressure on other key issues like fentanyl trafficking and democratic backsliding in Mexico, creating a political deadlock that limits US influence beyond migration policy.
Impact of Fentanyl and US Pressure
The escalating crisis of fentanyl in the United States, with over one hundred thousand drug overdose deaths annually, stems mainly from Mexican cartels, which manufacture fentanyl products (with precursors sourced almost exclusively from China) and smuggle them into the United States. This situation increased pressure on the López Obrador administration to act aggressively against these cartels. Despite the Mexican government’s high-profile arrests, such as that of Ovidio Guzmán, son of the notorious drug lord Joaquín “El Chapo” Guzmán, these efforts have remained sporadic and largely symbolic. They failed to disrupt the cartels’ operations or fentanyl production and trafficking in any significant way.
Additionally, reports from sources like Reuters exposed the Mexican government’s misleading claims about fentanyl lab busts and production. López Obrador, at one point, falsely asserted that no fentanyl was produced in Mexico, contradicting overwhelming evidence to the contrary.
In July 2024, US law enforcement arrested two significant figures from the Sinaloa cartel in a high-profile sting operation—Ismael “El Mayo” Zambada, a longtime leader of the Sinaloa cartel, and Joaquín Guzmán López, another son of El Chapo. While the operation was dramatic, it is unlikely to lead to a significant reduction in fentanyl trafficking due to the cartel’s extensive networks and redundancy systems.
There is a significant risk that the arrests will escalate violence in Mexico. This could occur within cartels—the Chapitos and Zambada factions vying for control of the organization—or between rival cartels. This could further destabilize regions already plagued by violence.
However, the arrest of Zambada presents a unique opportunity. As one of Mexico’s most influential cartel leaders, Zambada has intimate knowledge of the corruption networks that allow cartels to operate with impunity. If US prosecutors leverage this information, it could lead to further indictments of high-level officials in Mexico, potentially disrupting the political protection that shielded criminal organizations for decades.
Looking Forward to the Sheinbaum Administration
The US-Mexico counternarcotics relationship remains deeply strained, with cooperation at a low point despite the formal Bicentennial Framework for Security, Public Health, and Safe Communities. The López Obrador administration’s passive approach to law enforcement exacerbated cartel violence and failed to address the fentanyl crisis adequately. With the recent inauguration of Claudia Sheinbaum as president, many of López Obrador’s policies will likely continue. The United States faces a complex challenge in addressing migration and narcotics enforcement. Strengthening investigative capacities in Mexico and leveraging US arrests to expose corruption networks may be critical to breaking the cycle of violence and restoring the rule of law.
Sheinbaum has signaled her intent to maintain López Obrador’s policies under the “fourth transformation” framework—an initiative to overhaul Mexico’s social, economic, and political systems. As a close ally of López Obrador, Sheinbaum served as mayor of Mexico City during his administration.
On security, Sheinbaum has emphasized the continuation of socioeconomic strategies, echoing López Obrador’s “hugs not bullets” approach. However, as currently implemented, these programs appear insufficient to curtail cartel influence or violence. One potential positive development is Sheinbaum’s focus on increasing the number of investigators in Mexico. Given that the López Obrador administration significantly reduced the capacity of the federal police, this is a critical step in rebuilding law enforcement’s ability to confront organized crime.
What the United States Must Do: Policy Reforms
To improve the US-Mexico counternarcotics relationship and address the growing fentanyl crisis, the United States must implement several key policy reforms. First, it should demand greater transparency and accountability from Mexico in its law enforcement operations, particularly regarding efforts to combat corruption within the police and government. US assistance should be contingent on clear benchmarks demonstrating progress in reducing cartel influence and restoring the rule of law. Strengthening joint investigative initiatives between US and Mexican agencies is also crucial. The United States should support and encourage deeper cooperation that dismantles the corruption networks that protect cartel leaders and facilitate the fentanyl trade, share intelligence, and assist Mexico in rebuilding its investigative capacities.
Moreover, the United States must leverage diplomatic and economic pressure to push Mexico toward more robust cooperation in counternarcotics efforts. To improve cooperation, the United States must directly link foreign aid and trade agreements to meaningful anticorruption reforms and tangible improvements in law enforcement. In addition to addressing immediate security concerns, the United States should also focus on supporting long-term socioeconomic programs that target the root causes of violence and instability in Mexico. However, these initiatives will only succeed if backed by a strong rule of law, something the United States should strongly encourage the Sheinbaum administration to prioritize.
Finally, the United States should expand its operations to disrupt the fentanyl trade, mainly targeting the cross-border supply chains that link China and Mexico’s cartels. This includes enhancing maritime and land interdiction efforts to cut off the flow of fentanyl before it reaches American communities. Without coordinated reforms and pressure from the United States, Mexico’s struggle with cartel violence will continue to undermine regional security, with severe consequences for both nations.
What Role for the US Military?
The US military’s participation in counternarcotics is essential to a larger interagency strategy that leverages military capabilities to support law enforcement agencies that traditionally lead these efforts. Despite being primarily nonmilitary, these operations often demand resources that the military can best provide—leadership, logistics, surveillance, and rapid response capabilities—especially in conflict zones where these agencies face constraints or limited presence.
US Southern Command leads the Joint Interagency Task Force South, which focuses on detecting and tracking illegal trafficking within its area of operations. This supports US and partner nations’ security efforts by enabling the interception and disruption of these activities.
Furthermore, the military’s unique international reach and established ties with foreign defense entities allow it to play a vital supportive role in operations beyond US borders. This support can range from direct interdiction and intelligence sharing to regional stability initiatives that weaken transnational criminal networks and limit the operational capacity of drug traffickers.
In one effort, the US Air Force collaborated with Caribbean partners to target drug trafficking routes, using specialized aircraft and advanced surveillance to monitor vast ocean areas. Similarly, the National Guard Counterdrug Program bridged the gap between DoD and civilian agencies, pooling resources to address local and international narcotics threats.
In essence, the military’s involvement does not replace the primary responsibilities of domestic law enforcement but rather enhances them, helping to address complex transnational issues that demand an interagency approach. This collective use of assets and capabilities helps overcome the limitations of any single agency and justifies the military’s presence in what might traditionally be considered law enforcement territory.
Nicholas Dockery is a White House Fellow, Special Forces officer, United States Military Academy graduate, and Wayne Downing scholar. Dockery holds a master of public policy from Yale’s Jackson School of Global Affairs and previously served as a research fellow at the Modern War Institute.
The views expressed are those of the author and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.