It is a war that cannot be won except in the minds of bureaucrats that profit from it. There is not a single instance in the history of mankind where prohibition against self-medication has worked or even made things better.
In the meantime it is used as an excuse to shred civil liberties. The BATF and DEA should be disbanded and its officers retrained as border patrol agents.
If you can't get accross the border in the first place, it makes smuggling that much more difficult.
Adam Smith - The Invisible Hand Speaks.
The short answer is called capitalism. The drug trade is capitalism in its most raw form. Supply vs. Demand.
The demand is reletively constant in terms of the percentage of the population that will use drugs. The more successful the war on drugs is in restricting supply, the higher the price the available drugs will fetch.
The higher the price, and therefore the greater the potential profit, the higher the inducement to enter the drug trade as a supplier. The higher the inducement, the greater the risks that will be hazarded to engage in it. The higher the risks involved, the Greater the extremes those in it will go to protect it (bribery, murder, etc).
[is anyone seeing a pattern yet?]
The argument, "what about the war on murder, etc." is invalid. There is no profitable, widespread demand for murder or most other crimes with possible exception of burglary (much of which is committed to pay for expensive drug habits).
The argument that totalitarian governments are successful in stemming drugs is also invalid. They are no more successful than free countries, they just have harsher punishments, which require greater bribes to public officials to avoid. Even certain countries in Asia that execute drug dealers have drug problems (which they do not admit to).
Any conservative that understands the basic precepts of capitalism and supports the current war on drugs is suffering from cognitive disconnect. They are no different from liberals that believe welfare programs will solve poverty.
The only solution that works on either problem is instilling in people the idea that they are responsible for their own actions. Responsible people are much less likely to use drugs or end up on welfare.
As for the rest, punish and jail them when or if they commit other crimes. Double the penalty for the crime if it is determined that they were chemically impaired at the time.
It's an educational battle that must be fought every generation.
IMHO.