Prohibitionism has never worked and will never work. It gives the market to the criminals, which use their money to target more and more kids, and corrupt more and more the government. It leads to a vicious cycle making more and more people addicted to bad quality drugs.
In my country, heroin has been unofficially legalized to minimize the danger of AIDS (common sense), and since then the heroin consumption has almost disappeared.
The danger of drugs is negligible compared to the danger of the prohibition of drugs, which not only augment considerably the use of drugs, diminish their quality, but it raises huge black and grey market which corrupt the root of the democracy. Abraham Lincoln knew that very well:
"Prohibition... goes beyond the bound of reason in that it attempts to control a man's appetite by legislation and makes a crime out of things that are not crimes. A prohibition law strikes a blow at the very principles upon which our government was founded" -Abraham Lincoln, U.S. President