I don't think your government gives a fuck if it will be the next vietnam, if history is to go by anything, they will go there if they want and nobody will stop them.
A massive problem I see with making the cartels terrorists is I would bet there will be alot more human rights abuses in your own borders. What is stopping them from saying Juan from Texas is a terrorist because his brothers uncles cousin knowns of a dude in the cartel? Or even if he doesn't they can claim that and nobody can do anything about it.
Then even worse are the people of south america, anyone of them can be called a terrorist....
Sadly, the only way to stop the cartels is to remove human rights or it becomes one big clusterfuck of court cases