I suppose you could talk me out of this view, but it seems to me that the costs of full heroin legalization would far exceed the benefits. There’s a lot wrong with America’s current drug policies, but it’s also good that we don’t have heroin ads on Saturday morning cartoons, there’s no Heroin Lobby on the Hill, and you can’t buy heroin at the 7-11. That all seems pretty clear cut to me.It's worth going back to look at 19th century America, when basically all opiates were legal. This is from the Consumer's Union Report on Licit and Illicit Drugs, for my money still the best single overview of the drug issue:
The United States of America during the nineteenth century could quite properly be described as a "dope fiend's paradise."I think Yglesias is probably right that immediately legalizing all drugs tomorrow would lead to a great deal of social turmoil. But I think this is largely an function of our social conception of "hard" drugs as extremely dangerous, horribly addictive, and associated with criminals and deviants. Back in the 19th century, society had acceptable mainstream slots for opiate users to occupy, so having physicians that would literally give straight morphine to anyone that asked did not cause huge problems. The Lancet says that alcohol is the most dangerous drug in the world, bar none, yet our society manages to deal with it reasonably well because it's part of mainstream culture.
Opium was on legal sale conveniently and at low prices throughout the century; morphine came into common use during and after the Civil War; and heroin was marketed toward the end of the century. These opiates and countless pharmaceutical preparations containing them "were as freely accessible as aspirin is today."1 They flowed mostly through five broad channels of distribution, all of them quite legal:
1) Physicians dispensed opiates directly to patients, or wrote prescriptions for them.
(2) Drugstores sold opiates over the counter to customers without a prescription.
(3) Grocery and general stores as well as pharmacies stocked and sold opiates. An 1883--1885 survey of the state of Iowa, which then had a population of less than 2,000,000, found 3,000 stores in the state where opiates were on sale-and this did not include the physicians who dispensed opiates directly.2
(4) For users unable or unwilling to patronize a nearby store, opiates could be ordered by mail.
(5) Finally, there were countless patent medicines on the market containing opium or morphine. They were sold under such names as Ayer's Cherry Pectoral, Mrs. Winslow's Soothing Syrup, Darby's Carminative, Godfrey's Cordial, McMunn's Elixir of Opium, Dover's Powder,3 and so on. Some were teething syrups for young children, some were "soothing syrups," some were recommended for diarrhea and dysentery or for "women's trouble." They were widely advertised in newspapers and magazines and on billboards as "pain-killers," "cough mixtures," "women's friends, "consumption cures," and so on.4 One wholesale drug house, it is said, distributed more than 600 proprietary medicines and other products containing opiates.5 [...]
Opiate use was also frowned upon in some circles as immoral-a vice akin to dancing, smoking, theater-going, gambling, or sexual promiscuity. But while deemed immoral, it is important to note that opiate use in the nineteenth century was not subject to the moral sanctions current today. Employees were not fired for addiction. Wives did not divorce their addicted husbands, or husbands their addicted wives. Children were not taken from their homes and lodged in foster homes or institutions because one or both parents were addicted. Addicts continued to participate fully in the life of the community. Addicted children and young people continued to go to school, Sunday School, and college. Thus, the nineteenth century avoided one of the most disastrous effects of current narcotics laws and attitudes-the rise of a deviant addict subculture, cut off from respectable society and without a "road back" to respectability.
Alcohol is so deeply ensconced in mainstream culture because most of humanity grew up with it, but that's mostly an accident of history and biochemistry. It's easy to imagine a culture growing up with rampant opiate use (in fact, there have been some), and such a culture would have a much easier time dealing with opiates.
A few more points: first, if all opiates were legal, no one would use heroin. That's because heroin is a prodrug that is immediately metabolized to morphine in the brain—meaning it has exactly the same effect as morphine for about 1/3 of the weight, making it ideal for drug smugglers. Morphine is cheap enough to produce, though, that without the market-distorting incentives of the black market it wouldn't be worth the price of chemical conversion. Second, aside from the addiction, morphine has some of the fewest side effects of any common drug. About the only consistent one is constipation.