In my recent posts on marijuana legalization, got so lost in all the pragmatic reasons why prohibition is bad that I forgot the legalistic one: it’s unconstitutional at the federal level. The reason alcohol prohibition required the 18th amendment (and that its repeal required the 21st) was because it was well understood at the time that congress does not have the power to prohibit a product on its own. Where in the constitution is banning drugs of any kind an enumerated power? Well, the Controlled Substances Act does it anyway. There is clearly no distinction between banning a liquid drug and banning a plant drug, so the only thing prohibitionists can say to defend its constitutionality is that the constitution is a “living document” and our interpretation of its meaning has changed since the 1920’s. This, as I’ve explained in the past, is bullshit. Banning private drug possession or consumption in the privacy of one’s own home is not a regulation of interstate commerce. Protecting people from themselves is not necessary and proper for the implementation of any of the other enumerated powers. That it can theoretically enhance the general welfare is insufficient, as it must do so without stepping beyond the bounds of the powers expressly granted to the government. So you can add increased legitimacy to the list of benefits I cited before.