https://www.washingtonpost.com/news/in-theory/wp/2016/04/29/scientists-want-to-study-marijuana-big-pot-just-wants-to-sell-it/

Each week, In Theory takes on a big idea in the news and explores it from a range of perspectives. This week, we're talking about drug scheduling. Need a primer? Catch up here.

David T. Courtwright teaches history at the University of North Florida, where he is presidential professor. He is writing a history of pleasure, vice, and addiction with the help of a National Endowment for the Humanities Public Scholar Grant Award.

Since 1970, when President Richard Nixon signed the Controlled Substances Act, marijuana has been a Schedule I drug. Congress placed it in the most restrictive category of psychoactive substances, those with no currently accepted medical value and a high potential for abuse or dependence. The upshot was a renewed ban on marijuana, except for highly restricted research purposes.

I say renewed because Congress first prohibited marijuana use for non-industrial purposes in 1937. The Schedule I designation ratified the status quo, with one notable exception: The 1970 CSA actually reduced federal penalties for cannabis possession, a bit of Nixon-era liberality few people recall.