Since I don't think that Americans are willing to execute drug users, legalization is the only reasonable route to take.
The drug trade could be almost completely collapsed overnight if we adopted two simple strategies:
1. Legalized marijuana and sell it in a controled manner as we sell alchohol. It is probably less harmful (but not harmless) than alchohol.
2. Give addicts to hard drugs a prescription for the drug they use, and let them buy it for a nominal cost at a pharmacy. Believe it or not, this is how it was handled until about forty years ago. The doctor could write a presecription for, lets say, morphine, and would write "addict" in the cornor of the prescription. The pharmacy would then dispense the drug. It was a quiet, efficient and dignified way of handling addiction, and it resulted in fewer addicts than there are now.
Unfortunately, there are so many people making huge fortunes on drugs, including customs agents, police, DEA agents, politicians and financial institutions, that there is little hope that these forces would actually allow the problem to be solved.
The other force arrayed against actually solving the problem is the "moralizers". These are the same individualas who would have demanded Prohibition 80 years ago, but now the focus is drugs. Unfortunately, these people can't get past their moralization and solve the problem. These same people would for the most part be appaled if it was suggested that we execute addicts. They offer no realistic solutions to the problem except more of the failed War on Drugs.