Starting with alcohol prohibition in the 20's, mainstream-izing during the Nixon Era and escalating ever since, the Drug War has become an establishment staple that won't seem to go away. To a certain extent, it has become something of a cliche to consider resistance to the drug war is an inherently left-wing sentiment and the cause of mostly hippies and neo-hippies who do drugs themselves. While it is evidently true that more on the left are against drug prohibition then on the right (although the vast majority of the establishment democrats are passive to supportive of the drug war), there are also fundamental economic reasons to be against the drug war. In fact, the entire matter can be summed up in terms of property rights. Private property rights, under both axoims of self-ownership and homestead/possession.
Let us start with the concept of the natural right of each individual in their own person, to own and control their own body, free from aggression and coercion. This is the most fundamental property right there can possibly be. If people do not own themselves, then literally all other rights one can concieve of would cease to exist. All rights are inherently based off of this basic pillar. It should obviously follow that if one has a natural right in their own person, then they are "free" to injest whatever substances they please into their own body. This would include anything from food to cocaine. Such things are actions of the self, and therefore in no way constitutes the use of force against the person or property of others (which is the true definition of crime). What is the effect of prohibiting this voluntary human action of the self? A blatant violation of one's natural right in one's own person, to use and control their own body.
And there is more, homestead. One also has a natural right to freely exchange goods and services with others. Free Exchange and Free Contract. Prohibition of drugs also is a violation of possession/homestead, the free market economy. The effect of the prohibition is to deny a seller the natural right to sell the particular good/service, to deny a buyer the natural right to buy the particular good/service. And to deny the natural right of both to possess the particular good/service. Furthermore, the people's property rights in person and possession are violated further when they are thrown in jail for sale and possession. In short, it is a complete violation of the free market. It should be treated no differently than as if cars or meat were prohibited. Both cars and meat have potential for harm, but that does nothing to negate one's right to possess and exchange such things.
Of course, the drug war obviously requires billions of tax dollars, fiat money printing and therefore government spending. That most definitely creates an erosion of the property rights in possession, as you are increasing how much money is taken from people's taxes and the inflation from money supply increases raises their consumer prices. This is the inevitable result of balooning government spending. The drug war has been tied into foreign policy for a long time now, as the government sends military planes to spray pesticides on poppy plants in Afghanastan and coca plants in Columbia, which presents an extreme problem of sovereignty to boot, and a blatant violation of the property rights of the farmers and countrymen of those foreign countries.
On the more utilitarian plane, there is a basic reality of supply and demand. Reality should tell us that the demand for drugs will always exist, and the most the drug war can do in terms of supply and demand is lower the supply through the prohibition. Of course, in doing this, the effect is to create a defacto domestic black market for the drugs, with generally inflated prices due to the diminished supply. No matter what the government does, it will never realistically curb the demand. As a result, the effect is worse conditions and a real incentive for real violent crime.
Particularly in "lower-class" neighborhoods and ghettos, the environment created by prohibition is one where people have a very big incentive to turn to criminal means when dealing with drugs because of the inflated price and turf wars over the supply. Thus, the violent crime commonly associated with drugs is largely the result of the prohibition itself. It is inherent - when you criminalize voluntary human action in such a way, you are practically making people into criminals. The Organized Crime and chaos of the 20's during alchohol prohibition is a clear testament to this, just as today street gangs and border-hopping black market dealers are the direct result of the drug war. You are forcing some people to use criminal means to obtain, sell or use their desired product or service. And of course, there are the corrupt police forces that introduce the drugs back into the black market.
There is also simply a naturalistic consistancy about drug use. Someone who is addicted to heroine is naturally punished already through the health problems that it yields. Someone who drinks too much is naturally punished with liver and stomach problems. Someone that snorts too much cocaine is naturally punished with erosion of nose cartelidge. It seems that the natural result of such risky decisions already punishes these people, so why would you react by punishing them further? That surely makes no sense and makes the drug war seem more about vile, misinformed revenge for puritans.
And, what of personal responsibility? The prohibition functions to take away one's ability to be personally responsible for their own actions and has the state be an omnipotent nanny that takes responsibility for them, always under the instance that its "for their own good" and "for the public good" and such absurdities. Without the capabilitiy of free choice, genuine morality ceases to exist (as was part of the lesson from Clockwork Orange). The government or the majority are not all-knowing omnipotent sages that know what is best for everyone else, and they certainly do not respect one's ability to decide such personal matters for themselves. There is a term for people that are hellbent on dictating the personal choices and actions of others - lifestyle fascists.
Of course, there are always those that would ask the question, "But what if some guy does heroine and then goes off and murders someone?". This question presents a straw man to begin with. The crime itself would be the act of murder, not the fact that they do heroine. This would constitute very good and ethical reason to prohibit murder, but not heroine. The law could and should react to the murder by prosecuting and convincting within the bounds of a fair trail (if such things exist anymore). Another common theme is "but what about the children?". This is perhaps the most annoying and weak of all. If a child is coerced to endure being drugged, then obviously a case could be made for a crime. However, again, this does not provide a legitimate reason for drug prohibition.
The drug war has never been about morals or safety. It is a violation of the free market, a breeder of crime, an invasion of responsibility and a bastion of a police state. It is the manipulation of protective and puritan emotions in people by the government to gain support for an oppressive and counterproductive policy that also indirectly functions to shield established buisinesses and industries from competition (as in the case of the banning of industrial hemp). It doesn't matter if 95% of the population supported drug prohibition. It's a war on the American people and should be abolished. Private property wins. Big government loses.