1- Convince a lot of drug users to do all their possible to move in a country where laws on drugs are the weakest (Holland for example) and do their possible to convince people that drugs are not that bad so that most of the people get pro-drugs and that politicians follow on pressures and legalize.
2-Just keeping on, Internet now provides real infos on drugs and a lot of people start to realize they are not that bad and that we have been lied since we were born.
3-Find a way to make genetically modified plants that produce drugs, which souldn't be that hard with right equiepments, and spread hundreds of wild mass growing plants over the world so that people realize by themselves.
4-Wait for Jesus to come back and ask him to raise pure LSD mountains all over the Earth.
Seriously, I vote for 3. But medicine is so corrupted that people there will never do such experiments, but we can try to convince some scientists to do the jog