Bullcrap...
These Mexicans will pull a Saddam Hussein any chance they get....
There are two levels of ‘authority’ in Mexico. There’s the elected government, and the drug cartels. I think if the US went to an intense border control and made max effort for a month to control/stop drug flow, and just hint that it’ll continue unless the caravans halt....then the cartels would ensure they stop. That’s probably the more effective way of handling this episode.