Since Gary Johnson is now running for president, this occurred to me: how has no one done a study on the effect of medical marijuana dispensaries (which are now quite common in some states) on the illegal pot trade?  Does it hurt their business?  Does it cause them to alter their prices, or quality?  Do they compete with the dispensaries, or do they just open one themselves?  Do they try to occupy a different market segment?  This seems like economics study gold.

Alternatively, if someone has done this study, let me know!