Ok, then why don't we go occupy mexico and colombia for marijuana and cocaine production?
Because it's marijauna...and the Columbia thing is very touchy, we've already been down that road, I guess you haven't heard about the Maimi situation...
But, your question implies that we occupy countries based upon drugs...and drug production....and we don't, it ain't that simple
Also, do you bother a good whore? no, you don't, if she/he (whatever way you lean) is good about it, you let them continue...and that is what drug producting countries are...for the most part, they are 3rd World or developing countries, and the clients are developed countries...the drug nations provide a service, just like those countries with sex tourism...if they have issues, you don't get involved unless it really spills over.