First thing to pop into my head is civilian casualties and public backlash in Mexico.
Secondly, listen... If the U.S. was a person it would be a dope fiend who gets their shyt from their next door neighbor. There is clearly a really high demand from all walks of life in the U.S. and there is no end in sight. Drone strikes on cartels will create temporary power vacuums that will most likely be filled through violent means.
This might be an unpopular opinion but why not just legalize drugs and have them regulated and taxed like alcohol. You want some coke, MDMA, LSD, fent? Cool, go to the state sanctioned distribution center and get your shyt. That would solve a bunch of problems in the U.S. Much less of our people in prison, less police needed and I'm sure it would create jobs with newly legal industries.
Production for these newly legalized products is where the U.S. would run into problems because the cartels are the means of production.