While watching the show Weeds, I had a thought about the effects that prohibition have on the nature of the substances that are prohibited.
During Prohibition in the 1920s, the quality of alcohol was often very low because production was forced underground. Moonshine was distilled in rural locales and was often very dangerous to consume. Now, people can buy liquors in stores without worrying about going blind. Microbreweries across our country brew very unique, complex beers. Society benefits from all the choices. During Prohibition, beer production was probably non existent because of the facilities required for brewing beer.
In the same way, before abortions were made legal, they were very dangerous because they could be performed in sterile facilities by qualified professionals (b.n. Whether or not abortion is ethical is an entirely different issue).
What if marijuana were legalized, and marijuana began to have their own versions of microbreweries? Like with microbreweries, users could have greater access to much more diverse products. They would benefit because of higher quality goods, as well as knowing that their marijuana is safe (like drinkers know their liquor does not contain poison because they bought it from a liquor store). Furthermore, as alcohol is regulated, marijuana would be regulated, and therefore would be safer.