I'm replying as one of the only people I know who has never done drugs other than the occasional aspirin, dip, or beer (well, maybe more than occasional for the beer), so perhaps that makes my opinion invalid or puts me in some rarely invoked "protected class". That said, from my perspective, the fog that envelops the swamp comprising our various state and federal drug laws and their various and sundry capricious applications is a freaking miasma. I'm not advocating for wholesale elimination of all restriction around all drugs, but even that might be better than what we currently face. If I were king, drugs would likely be legal and it would be an individual's choice and responsibility to use or not use... thus ending the endless pork barrel spend that is the current radar-detector, radar-gun like arms race that keeps the war on drugs endlessly ongoing and endlessly profitable for bad guys on both sides of "legitimacy". But with that environment, there would be ongoing drug testing for ALL jobs. That would just be part of the bargain... if you want to get paid to work, you don't show up high or with residuals. As it stands now, people with no responsibility can show up for work high as a kite. Heck they can -and do- get high on the job. But remember, these are only people who work in low responsibility jobs... you know, folks like investment bankers, doctors, and lawyers.
Meanwhile you can buy and smoke dope legally in several states while concurrently breaking federal law.
I don't want a foolish consistency to be a hobgoblin for my little mind, but at least modicum of consistency would sure make things easier and saner.