I have been wondering why somebody isn't advocating a naval blockade of the west coast of Central America to intercept ships carrying precursor chemicals headed from China to the drug cartels in Mexico? We interdict drug smuggling ships, why not those bringing the raw materials?
This would be less likely to rupture relations with Mexico than sending special forces to attack the cartels. If there are legitimate uses of these chemicals, those could be let through and tracked to make sure they end up in non-cartel hands.
Ocean freighters aren't speedy, and satellites can track them easily. I'd imagine 2-3 Coast Guard ships could do the job. Maybe the east coast would need patrolling as well.
Do you suppose the cartels would begin flying in the feed stock for their fentanyl factories? It might be too expensive, nonstop China to Mexico is a long flight, Google Maps says roughly 21 hours each way. Most planes can't do that distance nonstop.