Over the past year, a range of presidential candidates and members of Congress have argued that the United States might benefit from conducting military strikes in Mexico against Mexican drug cartels and drug labs. The New York Times reported several months ago that former President Trump would seek to use military force in Mexico if he is reelected and that Trump’s “notion of a military intervention south of the border has swiftly evolved from an Oval Office fantasy to something approaching Republican Party doctrine.” Some Republican House members went even further and introduced an authorization to use military force (AUMF) against fentanyl-trafficking cartels, a proposal with more than 20 co-sponsors.

While there is ample commentary about the wisdom of this idea as a policy matter, there is limited analysis about the legal questions that would arise if the United States sought to use force in Mexico against drug cartel members or drug labs without the Mexican government’s consent. This piece considers some of those issues. In sum, executive branch lawyers could argue that such action would be consistent with past presidential uses of force, even without an AUMF, but it would be very difficult to defend under international law and, as others have pointed out, would be seriously misguided as a policy matter. 

Ashley S. Deeks & Matthew Waxman, Using Force Against Mexican Drug Cartels: Domestic and International Law Issues, Lawfare (December 13, 2023).