With stuff like heroin and cocaine, I'd still like to see massive disincentives of usage if the prohibition were to be lifted. I'd also would want the phase out of the normal syringe and replace them with single-use ones to prevent the spread of blood borne diseases.
Elimination of the welfare state would do this. If I'm not covering your and your family's expenses, I'm probably not going to care as much if you want to ruin your and your family's lives.