My friend Daniel Charlies (D.C.) writes in defense of the government's right (society's right by proxy) to prohibit drug use in the broad sense (i.e. even traditionally legal drugs, tobacco, alcohol, etc.) for humanitarian reasons, otherwise known as paternalism. True paternalism means that this is OK even after establishing that a particular behavior is otherwise "victimless," meaning others are not harmed. There are certainly arguments that drug use, driving without seatbelts, etc. are not truly victimless, but we leave those for another time.
Paternalism vs. personal liberty boils down to, "should people be allowed to make their own bad decisions?" D.C. writes:
For any given thing that has no demonstrably irreplaceable good value and which does have demonstrable negative effects to a significant portion of a population of people, there can be no moral justification for permitting it.
I think this is as good a case, stately concisely, for legal paternalism as I have heard. Now there is the sticky question of "demonstrably irreplaceable good." I leave a thorough discussion for another time, but I would say, in passing, that when large numbers of people engage in some activity (here we refer to the use of various recreational drugs, legal or not) indicates that they derive some pleasure or satisfaction therein, which should count as a good. I assume D.C. doesn't deny this, but considers this "replaceable" or a least not "demonstrably irreplaceable," which is debatable, at least.
The main problem I see with this argument is that it proves too much. No one, essentially, ever uses any sort of drug with the intent of suffering great harm, dying early, etc. And of course, not everyone does experience a bad outcome. There is certainly risk associated with drug use, indeed nicotine and alcohol, our two main legal recreational drugs, are some of the riskiest, and have some of the worst outcomes, if you look at the numbers. But demanding that any permissible behavior not harm any significant number of people is a damn restrictive standard. My cholesterol is elevated (only slightly by the old standards, a bit more by the new, tougher ones) and I am trying to get it down, but I still had a mushroom cheeseburger the other day. In fact, you don't really even need to know anything about a person's cholesterol level--as a statistical fact, eating highly fatty foods elevates the risk of arteriosclerosis and heart attacks, which means some people die from eating cheeseburgers. There are plenty of healthier ways for just about anyone to get protein, calories, and nutrition, so cheeseburgers don't supply an "demonstrably irreplaceable good." Of course, I would say that cheeseburgers are irreplaceable, in that I know of no healthy cheesebuger replacement that tastes quite so good! But if I'm allowed this, certainly smokers can say the same for their tobacco--or weed. So this argument allows the government to ban cheeseburgers for our own good. Or is that just what someone else thinks is our own good?
And of course, the list goes on from there. Even with a helmet, riding a motorcycle is risky, relative to a sedan. Or driving most sports cars instead of a Volvo, irrespective of seatbelt use. Sex is risky--even when monogamous and legally sanctioned, you can have a heart attack, or stroke. I suppose sex might escape as a "demonstrably irreplaceable good," but you might not get universal agreement on that! "Not tonight dear, you might have a heart attack."
A life spent minimizing risk probably wouldn't look like much of a life to most of us. I believe it is the very essence of personal freedom to assume your own risks and reap your own rewards. After Vioxx was pulled from the shelves by Merck, many of its customers clamored to get it again, even after knowing about the elevated risk of heart attacks. Why was this? Because they suffered from chronic pain, and other medications hadn't been effective. Eventually, the FDA agreed that this Vioxx use was OK, as long as users were informed about the risks.
From what I know, Merck behaved badly, and pharmaceutical companies have behaved badly in general, by suppressing inconvenient or embarrassing data. Informed consent by consumers depends on open access to any and all relevant data. But if that standard is met, people should have wide latitude to take whatever they want. Who are we (society) to tell someone they can't trade a risk of heart attack for relief of chronic pain? And once we are there, the case against marijuana looks a lot weaker.
The "gateway effect" is probably the greatest cited risk of marijuana. But a survey of the evidence, including twin studies, suggests it is a) not so large and b) there is no real evidence of a neurochemical basis for the gateway effect. In other words whatever modest gateway effect marijuana has, it is likely to be social and environmental factors. My personal bet is that the "barrier of illegality" is the biggest source. Once you cross the line to try marijuana, the illegality of harder stuff is less daunting. The answer: move the line of illegality! I know of no evidence that marijuana is any worse than alchohol, indeed quite the opposite. Bil Bennett, among others, likes to dismiss this sort of talk as "dorm room bull session" stuff. Nonsense! The drug war and prohibition have enormous social and economic costs. The cost of incarceration, interdiction, and the loss of economic productivity from imprisoning simple drug users is huge, not to mention the pure human suffering of destroyed lives.
Again, I by no means endorse or promote smoking. If, heaven forbid, my kids ever try it, there will be hell to pay. But I'm just putting the "pater" into "paternalism!"