Writing for City Journal, Theodore Dalrymple draws a brilliant parallel between the law on drugs and speed limits (yes, that’s right, between the prohibition on one kind of speed and the restriction on the other):
It should be obvious that speed limits, though frequently broken, still have the effect of keeping speeds down. Similarly, drug laws – if enforced with any degree of diligence – restrict the supply and therefore the use of drugs. The fact that illegal drug use is declining in this country, while the problem of so-called ‘legal highs’ is getting worse, would appear to be bear this out.
But there's another libertarian argument that deserves an answer: many people manage to enjoy drugs without doing themselves serious harm, so why should they be punished just because others are not so judicious in their own use?
Dalrymple points out that much the same argument could, and presumably is, made in respect of speed limits – i.e. applying the same limit to everyone curtails the freedom of those who are capable of driving safely at a higher speed. Given that this is the case, shouldn’t "responsible citizens… be able to determine for themselves at what speed to drive":
One might add that even if you are capable of handling your speed (of either variety), there are others who will not be. Therefore, in the absence of a means of tailoring different limits to different individuals, the same limits must be observed by all.
There is a further parallel that Dalrymple does not mention.
Someone who can safely drive at high speed may not be a direct danger to others, but they would encourage other, less capable drivers to match their speed. The same applies to drug use – after all, who is more likely to encourage a vulnerable person to try drugs: someone who makes a mess of their lives as a result or someone who coolly evades the consequences of their wild ways?
Libertarians so often see the law as something that it done to the individual by the state. But a more conservative view is that the law is something that, through democracy, we make together – and that, through society, we uphold together.