An unthinkable amount of money has been spent and made from the drug war for highly questionable ROI to the public.
What type of reduction in police work would take place if the drug war was ended today? 20%? 30%?
The war on drugs is a job machine. DEA agents fly around like international playboys from the books I've read. Plus international governments get tons of money from the US to run their own interdiction programs.
There has to be some level of influence to keep the 'war' going from these perverse incentives.
Only if you exclude people working for the public sector from you know, the public.
Those things create jobs for voting constituents. That's the main ROI here. Reduction in crime, drug use and increased security are just beneficial, but not necessary side effects of these initiatives.