Go back and re-read previous posts.. Incarceration is one factor in a complex formula.. Making federal involvement smaller, getting people to start taking responsibility for raising their own children and instilling a value system that resembles responsible adulthood is another piece (even less govt involvement), education, community involvement, and a return to a public system that doesn't support you through welfare, free hospital care, food, etc if you choose to be a drug user and fry your mind (even less government), a reduction in the stupid spending associated with the prison system (even less government), etc, etc, etc...
All great ideas that would solve more problems than just the drug problem. The only way this could happen is to elect small government, libertarian minded conservatives at all levels of government. A major undertaking not likely to happen overnight but we can always hope.
Add all this to a complete revamp of our prison system where people know that they are actually going to be held accountable for their crimes.. A system where 20 years really means 20 years.. One where people actually fear prison rather than laugh at it...
This is where the money comes in, the cost to house prisoners for that period of time is staggering, in order to make a significant dent with this method it's going to cost us Trillions.
And you'll have less people going to the pen...