The poppy question is an important one.

However,

1. Would the Afghan farmers growing opium make as much per hectare if they switched to hemp (including possible reduced security cost if they make the switch)? Part of the reason it’s been difficult to get many opium growers to switch to something else — for example, potatoes — is that it would cost them income.
2. How about pharma companies buy the opium to use in legal medications? But there are two big problems with that. First, legal opium growers, primarily in Turkey and India, would be unhappy. A lot of the current legal supply is locked in with longer term contracts that wouldn’t be the easiest to break. And second, heroin traffickers would be unhappy, and would likely use violence to protect their opium supply. That means security costs might actually end up higher, not lower.