His crime -- such as it was -- was answering "no" to question "f" on the form one fills out to purchase a handgun, Form 4473.
Are you an unlawful user of, or addicted to, marijuana or any depressant, stimulant, narcotic drug, or any other controlled substance? Warning: The use or possession of marijuana remains unlawful under Federal law regardless of whether it has been legalized or decriminalized for medicinal or recreational purposes in the state where you reside.
Based on known statistics of how many people consume weed -- 100% of them unlawfully according to Federal law -- we know somewhere between 15,000,000 and 25,000,000 people lied their asses off on that question last year. (And the year before. And the year before that, etc.) That's just weed. If you really believe no meth heads, coke heads, junkies, or pill poppers "legally" purchased firearms last year by lying on that form, I have a bargain on some beachfront property in Florida I'd like to talk with you about.
Guess how many were prosecuted for it as a stand-alone crime? Did you guess zero? Wrong! The answer is one; Hunter Biden.
There were two others in the last few years, both of whom were charged as part of a large drug conspiracy.
Besides, there's no definition of "user" there. I might have had some weed last week. I might have some next week. At the moment, though, I guess I'm not a "user of, or addicted to, marijuana."