Problems with Legalizing Opium

A new IWPR piece mentions several arguments against legalizing opium production in Afghanistan. Some, such as the fact the process of licensing would be corrupt, don't seem convincing to me given the difficulties in eradicating the crop and the effect it has on poor farmers. More convincing was the concern that Afghanistan did not have the security infrastructure to regulate legal production, which combined with the greater market value of illegal opium means legalization's main effect might be making it impossible to eradicate illegal opium fields due to confusion over their legality. That's obviously a problem, but not a long-term one if there is greater investment in Afghanistan's security and political infrastructure, something also need for long-term stability and defeating the Taliban/al-Qaeda militants who continue to plague the country.