The images from Mexico looked like a modern global battlefield. Security forces engaged in torrents of gunfire on the beach. Commercial flights into Puerto Vallarta promptly canceled as military helicopters took up airspace to run strafing fire on narco positions below. Highways filled with stalled traffic as buses burned along major routes, the smoke sending visible plumes across the city.

The torrent of violence followed a Mexican military operation Sunday that killed Nemesio Rubén Oseguera Cervantes, known as “El Mencho,” the leader of the Jalisco New Generation Cartel, or CJNG, one of the most powerful criminal organizations in the hemisphere. Retaliation moved quickly. Cartel organizations launched an onslaught of armed convoys and road blocks that torched buildings and gas stations in at least 20 states around the country, grinding an entire nation to a halt. In the violence, at least 70 people have died, 25 of which were Mexican military forces. 

In an after-action press conference, Mexican authorities were quick to frame the operation as a strategic success — a symbol of cross-border intelligence cooperation and another blow against organized crime.

But when reporters asked about the weapons recovered during the raid targeting El Mencho, Mexican Defense Minister Ricardo Trevilla Trejo offered a more unvarnished assessment. “Eighty percent are of North American origin,” he said plainly, roughly the same proportion of the nearly 23,000 firearms Trejo said the Mexican administration has confiscated since October 1.

The U.S. has helped create cartels more heavily armed than at any point in their history.

Narco organizations have evolved from illicit trafficking networks into heavily armed forces capable of blunting military grade law enforcement across entire regions. That escalation is not an anomaly. The United States — with its vast civilian gun market, weak barriers to arms trafficking, and law enforcement gaze fixed largely northbound — has helped create cartels more heavily armed than at any point in their history, a transformation that has destabilized Mexico, cost billions of dollars, and claimed thousands of lives on both sides of the border.

And while America watches from next door — calmly stirring its tea as cartel violence becomes political currency for tougher borders and even fantasies of military intervention — it has largely avoided confronting its own role in arming its supposed adversaries to the hilt.

The Iron Pipeline 

There are only two highly regulated legal gun stores in the whole of Mexico, so it is hardly controversial or new within law enforcement circles that America has long been an armory of illicit firearms for Mexican organized crime. In 2006, after the Mexican government began deploying soldiers to combat organized crime, cartel fighters began sourcing American firepower to near parity with the Mexican military. This coincided with a liberating time for American gun owners after the U.S. assault weapons ban lapsed in 2004. As a 2013 Cambridge research report found, the re-release of American assault rifles coincided with murder rates spiking in Mexico. This supply chain, through which America effectively dumps 200,000 firearms into Mexico each year, is known among gun policy experts as the “Iron Pipeline.”

The Bureau of Alcohol, Tobacco, Firearms, and Explosives, a law enforcement agency long constrained by political pressure and an aggressive gun lobby, could do little more than document the flow. Between 2014 and 2021, the agency reported that nearly 70 percent of firearms submitted for tracing by Mexican authorities originated back in the U.S., a figure federal agents and trafficking experts have consistently warned understates the true scale of weapons moving south.

While American gun companies reported record profits, their weapons were simultaneously transforming Mexican criminal mobs into paramilitary cells able to rout state military forces.

The result of that armament has been staggering: Mexico has recorded more than 463,000 homicides since 2006, alongside a parallel crisis of more than 130,000 people missing or disappeared. Much of the bloodshed has come at the muzzle of weapons trafficked north-to-south across the U.S. border.

In a previous attempt to arrest El Mencho back in 2015, cartel forces shot down a Mexican military helicopter with a .50-caliber rifle. The crash killed nine soldiers, with the gun later being traced back to a gun store in Washington state. In 2019, Cartel del Noreste conducted a two-day campaign of terror, pouring gunfire into the small town of Villa Union. In the aftermath, 23 people were dead, and authorities recovered a cache of weapons sourced from Houston. That same year, three American women and their six children were killed while living in Sonora when their Mormon community was besieged by sicarios. Two of the rifles used to kill them were bought from New Mexico and Arizona. Just last year, The Intercept recovered made-in-America rifle ammunition, including spent rounds from a factory owned by the U.S. military, at the the scene of a bloody cartel gun battle at a village in Michoacán. 

In the aftermath of El Mencho’s killing, a video appears to show CJNG fighters in Jalisco mounting an ambush, with one gripping a Barrett .50-caliber rifle — a weapon manufactured in Murfreesboro, Tennessee. Another clip posted on X shows what appear to be narcos unleashing a barrage of gunfire at Mexican authorities with an FN SCAR, a rifle assembled in Columbia, South Carolina.

Too Little, Too Late

There was no federal arms trafficking law on the books until 2022, which left U.S. authorities with few tools to charge gun runners for over a century. Meanwhile, a politically beleaguered ATF spent decades failing to properly inspect America’s nearly 80,000 gun dealers, allowing repeat violators to stay in business. While Customs and Border Protection has the clear authority to stem the outbound flow of weapons, their institutional fixation on migration and drugs has meant they intercept only a small fraction of the firearms flowing into cartel hands. 

When Mexican authorities filed a landmark lawsuit against U.S. gun manufacturers in hopes that Washington might finally intervene, the U.S. Supreme Court — backed by a conservative majority installed during Trump’s first term — effectively shut the case down, ruling that federal law shields gunmakers from liability.

The defining asymmetry of the modern drug war is not migration or narcotics, but American guns.

As a direct result of America’s blind eye to arms control, these hyper-armed Mexican syndicates have diversified their criminal portfolio. By capitalizing on America’s orchestrated thirst for opioids, Mexico became the leading source of fentanyl, shifting the drug war’s deadliest toll north of the border. In 2023, more than 105,000 Americans died from drug overdoses, far exceeding Mexico’s roughly 20,000 to 30,000 cartel-linked homicides annually — a grim inversion of the drug war’s human cost.

In a bid to bring stability to their country — and in doing its due diligence over America’s overdoses — Mexican authorities have dismantled more than 2,000 clandestine drug laboratories in recent years, many linked to fentanyl production raids that routinely uncover compounds armed to the teeth with U.S.-sourced firepower. Each lab, a Mexican diplomat once told me, is a “mini-Waco” in terms of firepower.

Even if America could snap its fingers and stop the drug trade tomorrow, the cartels have branched out. Extortion — taxation imposed at gunpoint — has become a multibillion-dollar pillar sustaining their criminal fiefdoms.

Human lives have borne the brunt of this violence, but the financial toll has been staggering as well. Since 2007, the United States has spent more than $3 billion in bilateral security assistance to Mexico under the Mérida Initiative and roughly $400 billion more on domestic immigration and border enforcement — a backward attempt to shield itself from the consequences of its own weaponry and the displacement driven by that violence.

For years, Washington has framed cartel brutality as a threat arriving from elsewhere, something to fortify against, sanction, or even confront militarily. Yet the defining asymmetry of the modern drug war is not migration or narcotics, but American guns: The United States has poured hundreds of billions into containing the fallout while leaving largely untouched the marketplace helping to produce it.

Americans enjoy the constitutional right to keep and bear arms — a right that’s deeply embedded in the country’s political identity and culture. But keeping arms carries a much larger obligation: being responsible for where those weapons ultimately end up. Until the United States learns to build a wall against the outward flow of its own firepower, the drug war will remain a shared tragedy — sustained not by inevitability, but by what America allows to leave its hands.