Done.
I wouldn't say get rid of it completely, I'd say put a lifetime max. Drug test. Any failures are considered probable cause for police investigation. Arrest can be avoided by getting into a program for first offenders AND turning over your supplier. Failure in the program gets your benefits cut and you get removed from all other gov't programs (food stamps, section 8 housing, etc).
The cost savings in people cut will pay for the cost of the program.