As to opiates and cocaine, the health drawbacks are apparent, as well as the opportunity to become addicted. I hate to admit it, but I support the prohibition of these products for the preservatin of public health.
However, E and pot are inherently non-addictive. People do become dependent on these drugs, but only to help cope with their lives, not to quench a physical addiction. As far as gateway drugs, if you do a survey of heroine and cocaine users you will probably find that close to 99% abused or used alcohol at some point. Alcohol is the real gateway drug.
For pot, I think a short term fix would be to legalize the smoking of marijuana on your own property, and legalize the growing of marijuana on your own property. The government would be in control of the seed (they have the best shit anyway). However, it would still be illegal to buy or sell marijuana. This wouldn't stop sharing, but it would stop pushers selling to minors and supporting "terrorism" through the sale of narcotics. Also, marijuana use would not have an impact on people's financial responsibilities. "Fight Terrorism, Grow Your Own" should be the new slogan from the Drug Czar's office. Or how about "Just Say Grow". Anyway, for those who have smoked or been around those that smoke, marijuana is just not the evil weed that it is made out to be. Yes, it can be a detriment to some peoples lives, but it is not the drug that is driving them, but rather a self imposed numbness that they require to ignore their responsibilities. For others, it's a nice relaxing afternoon in front of the TV.