Decriminalization is fine, and government regulation in order to destroy the black market, and provide safer manufacturing by scientists and professionals. Also, this means all substances, not just marijuana. The fact is, the 'war on drugs' only puts pressure on the black market, causing prices to skyrocket and attracting criminals and drug lords. Drugs will always get in, and people will always buy, period. The only difference is that if it's illegal, our money lines the pockets of drug lords while addicts in need of therapy get thrown in jail. Substances available for recreational and medicinal usage would be introduced under a limited system just as alcohol is currently. Medicinal purposes for substances deemed beneficial after adequate research should be granted by doctors and psychiatrists for their patients.
Harm reduction education programs should be sponsored and required to teach responsible usage. Are people suddenly going to become mindless addicts if drugs are legal? Of course not. Drugs are harmful if abused, and if people aren't educated about the substances and risks involved. Should cars be illegal because drivers can kill themselves & other pedestrians if they don't drive safely? No, because we have extensive education and training on driving safety required before obtaining permits, we've learned to drive responsibly. In the same way, the harm of drugs is not from the drugs themselves, but from ignorance and lack of information. Permits should be required for purchasing substances. It would be similar to alcohol (21+) except that a doctor's approval must be given, medical tests, and testing on drug knowledge and safety would all need to be passed.