The idea that academia is somehow prevented from engaging in this field because it's federally illegal is not credible and it tarnishes the integrity of the field.
I imagine that in some locales, the political climate is such that what Thriptic is saying is quite the reality -- it is much too risky.
That being said, with acceptance of cannabis legality growing, there does seem to be a shift where more formal organizations are involved in research, like the CMCR (https://www.cmcr.ucsd.edu/) mentioned in the Factcheck article. CMCR is located in the University of California in San Diego -- it is not surprising to find out that a formal research base is in a state more politically and legally friendly to cannabis.
Source?
In order to perform a clinical trial with marijuana, by law investigators would need to get an IND (investigational new drug) application approved by the FDA as FDA does not recognize marijuana as a safe and effective drug for any indication. Part of this involves DEA review, and DEA will almost certainly say no. Let's assume for the sake of argument that you do not care about getting approval to run your study. If you do not get an IND approval and you run a clinical trial anyway, your physicians will almost certainly lose their medical licenses, all participants will be subject to multiple criminal offenses, the group will lose all their funding, they be slapped with enormous amounts of fees, and participants will likely lose their university and / or hospital appointments.
https://www.fda.gov/NewsEvents/PublicHealthFocus/ucm421163.h....
https://www.fda.gov/AnimalVeterinary/ResourcesforYou/ucm2681....
I don't have a concrete example for as to what will happen because to my knowledge no one has been stupid enough to give the FDA the middle finger and run an unlicensed clinical trial. FDA would never let this go unanswered because it would completely undermine their regulatory authority and set a horrible precedent. In effect, this is a perma-ban level offense, and people that do it should expect to get massively punished.
It only took you 3 coarse and unhelpful posts to answer my legitimate question. Thanks for your cooperation. (5 Whys? Only 3 Whys were needed here.)