For decades, U.S. border enforcement has been at the center of the fight against drug trafficking. Sophisticated detection technology, expanded patrols, and tighter inspection procedures have transformed how Customs and Border Protection (CBP) and the Department of Homeland Security (DHS) monitor the flow of goods and people across the southern border. Yet despite these efforts, marijuana mules—individuals who physically transport cannabis across borders—continue to operate. The persistence of this phenomenon reflects not only the ingenuity of traffickers but also the policy contradictions created by uneven legalization and federal prohibition.

Strengthened Border Infrastructure

U.S. border strategy has increasingly shifted toward ports of entry, where most illicit drugs are seized. This focus aligns with data showing that traffickers prefer the cover of legitimate trade and travel rather than remote desert crossings. At high-volume crossings such as Laredo, Brownsville, and San Ysidro, non-intrusive inspection (NII) systems scan vehicles and cargo containers for anomalies, while canine units and advanced analytics supplement detection. Federal investment in these technologies has improved interdiction capacity and allowed more vehicles to be screened without significantly slowing commercial flows.

Still, gaps remain. Inspector General reports have pointed out that utilization rates vary, equipment downtime reduces coverage, and some ports lack consistent performance metrics. These weaknesses, even if minor, provide opportunities for traffickers who rely on volume and chance to move their products.

The Decline of Marijuana as a Cartel Priority

While fentanyl and methamphetamine dominate cartel operations today, marijuana has not disappeared from the smuggling landscape. Large seizures—sometimes several thousand pounds in a single truck—underscore that cannabis still flows across the border. This persistence is tied to uneven market conditions: in states without legal access or where legal cannabis remains expensive due to taxes, smuggled marijuana can undercut the price of licensed dispensaries.

In effect, marijuana is no longer a leading export for cartels but remains a supplemental revenue stream. The economics remain straightforward: as long as there is demand for cheaper or untaxed cannabis, someone will be willing to supply it.

Why Mules Accept the Risk

The role of the mule highlights the human dimension of smuggling. Recruiters target people facing financial hardship, promising quick cash for a single “delivery.” Some couriers may not even know the full extent of what they are transporting, while others knowingly gamble against detection, believing the odds are in their favor.

Federal law ensures that the consequences are severe: a mule caught with bulk cannabis faces felony charges, years in prison, and heavy fines. Yet the lure of profit and the belief that marijuana is a “less serious” drug compared to opioids convinces some that the risk is manageable.

Policy Contradictions at Play

The real driver behind continued marijuana mule activity is the policy mismatch between state and federal law. More than half of U.S. states have legalized cannabis in some form, but at the federal level it remains classified as a Schedule I substance. This contradiction ensures that cross-border transport is treated the same way as smuggling fentanyl, even though the public perception—and in many cases the local state market—treats cannabis as a regulated commodity.

The result is an enforcement paradox: border officers are required to dedicate resources to seizing a product that many U.S. states now tax and regulate. This leaves marijuana mules in a unique position, operating in the gray zone between shifting cultural acceptance and unyielding federal law.

The Path Forward

Closing the smuggling gap requires more than technology. Sustained investment in inspection infrastructure will continue to make trafficking more difficult, but the longer-term solution lies in policy alignment. Federal reform, whether full legalization or a harmonization model with states, would undercut the arbitrage opportunities that sustain smuggling. Without the price and access gaps created by today’s fragmented policies, the economic incentive for marijuana mules would shrink dramatically.

Until then, border security will remain locked in a cat-and-mouse struggle, and cannabis couriers—despite the risks—will continue to roll the dice.