The moment one argues in favor of liberalizing drugs people accuse him of being a drug addict: i have not drugs, do not do drugs and do not intend to do drugs. I care for my brain. Just like i do not smoke because i care for my lungs and i do not eat junk food because i care for my heart.
That said, i find the whole war on drugs declared by the USA utterly ridiculous. It has not even slightly dented drug consumption in the USA and it has created real wars in half of the world. Thousands of people die every year in Mexico because of the drugs bought by people in the USA and guns sold by stores in the USA. (See The other war on drugs). Tens of thousands of people are in jail in the USA for having used drugs, costing the taxpayer a fortune. The overall price paid by the world for this "war on drugs" has been colossal. I miss the point.
In 1729 China banned opium. In the 1780s Western traders started smuggling opium into China. In 1839 the imperial emissary Lin Zexu arrested 1,700 Chinese opium dealers in Guangzhou, seized tons of opium from foreign traders and wrote a letter to Queen Victoria of Britain urging her to stop the opium trade. The result? Britain attacked China in full force (the "Opium War"). Then in 1919 it did precisely what the Chinese had asked: it banned opium. Between the 1780s and the 1910s, however, opium accounted for a staggering amount of revenues. It created the wealth of European and American families, a wealth that funded many great cities of the USA and of Britain. Some of the greatest cities of Asia (Guangzhou, Mumbai, Hong Kong and Singapore) owe their power to the opium trade. In modern times the wealth of one of the richest countries in the world, Switzerland, has been created thanks to, among others, money deposited in its banks by druglords.
Of course, this is not the only case of "criminals" who became rich and were eventually "forgiven" and accepted by society. Think of the pirates of the Caribbeans, whose descendants now run "Atlantis" in the Bahamas. That does not mean that we should legalize piracy. However, drugs are different: they are not an assault by one person over another person. They are just like fast food, cigarettes and many other harmful hobbies. If you want to harm your health instead of, say, reading Dostoevsky or listening to Shostakovich, why should the government interfere?
The same government that once bombed Panama and arrested its dictator Noriega for helping the drug trade now supports the government of Afghanistan, which would not survive without its vast trade in heroin.
When i was in Peru at the peak of the war against cocaine, a farmer told me a simple truth (that later i heard in more ornate words by a president of the country): "If Northamericans want babanas, we grow bananas; if they want coca, we grow coca. We only want to feed our children. You decide what we grow." It makes no sense to punish the producer: people will grow drugs for as long as it is lucrative, and gangsters will get very rich smuggling them into the USA for as long as Northamericans want them. If the USA is serious about fighting a war against drugs, at least start shooting at the consumers and let along the producers, who are simply farmers and businessmen just like any other.
We don't bomb factories that make the worst polluting plastic, nor do we bomb McDonald's that is probably responsible for millions of heart attacks around the world. The government does well when it educates people about the risks of consuming such substances, but that is how far it should go. One can list many, many, many habits that are harmful, and many of them are as addictive as heroin (e.g., watching soccer). Let people decide how they want to waste their hard-earned money and tax them. And use some of the taxes to promote the benefits of buying bananas and oranges instead of heroin.
Opponents of the liberalization of drugs are afraid that society will have to pay for a growing number of rehabilitation centers. It seems to me that the exact opposite will happen: a better educated public will stay away from drugs. I also suspect that a lot of kids try drugs precisely because they are illegal, just like kids in the USA can't wait to be 18 so they can get drunk. Sometimes prohibition is the best form of advertisement. In any event, my opponents should use the same argument against fast food: we all pay the price for obesity, high cholesterol and heart attacks (it affects the cost of health care in general). Should we ban fast food? Should we ban all fat food, from meat to milk? Personally (being a vegetarian), i would be very happy if governments started taxing meat-eaters and fast-food joint patrons more than healthy eaters. That is one strategy i would totally approve: let's tax substances proportionally to how much damage they cause to health and to how addictive they are.
I like the idea that some substances are banned in public spaces (where i live alcohol is banned on beaches and smoking is banned in any building other than private homes). I find it very annoying to be around people who are smoking weeds (i like neither the smell nor the attitude): it is perfectly fine with me if, initially, we limit the liberalization of drugs to private residences. What you do in your house is really not my business. As long as you don't bother anybody else, it shouldn't be the government's business either.