One feature of modern political debate is the readiness of people to say something "should be banned".
The thing to be banned - which I will now call [B] - can range from drugs to obscene art, from fox hunting to animal experiments, from prostitution to absinthe, and from blasphemy to homosexuality.
There are dozens of examples, and this tendency is shared by the left, right, and centre.
However, from a legal perspective, to ban [B] is not actually to eliminate or extinguish it.
Sometimes [B] continues on as before, but slips down the back streets or dives underground.
Or sometimes [B] does actually stop in practice - like say bear baiting or cockfighting - though this can often be because of cultural change rather than legal change.
It may even be that the consequences of banning [B] are such that one will be deterred from doing [B], and sometimes this can work in practice, though the deterrence theory of punishment is generally questionable and has always seemed to me to be unfair.
In all cases, what banning [B] means is that if [B] now happens it can be attended by certain consequences.
This is because law is not actually any good at banning things like [B] but for providing for sanctions and liabilities should [B] happen again.
To use the law to ban something is not to invoke some magical power to prevent it happening.
Modern criminal law actually does not seek to ban things, at least not expressly. Instead the usual criminal statute will say that to do [B] shall "be an offence".
This means that the police and courts will deal with incidents of [B] in a certain way, and so in turn (if appropriate) will the prison and probation services.
To ban something is not the end of a phenomenon, but the introduction of new knock-on effects.
All this is straightforward in the mainstream of criminal activity, the endless and depressing daily tally of dishonest acts and physical assaults. It is also entirely appropriate for the most serious examples of dishonesty and violence.
I am not in the least sentimental about those who engage in serious criminal activity.
But dealing with mainstream criminality through a grim system of offences and sanctions is not the same as dealing with issues which can (arguably) have wider and contended religious, normative, sexual, or cultural significance.
And these can range from drugs to obscene art, from fox hunting to animal experiments, from prostitution to absinthe, and from blasphemy to homosexuality.
Sometimes it may well be wrong, and perhaps it really should come to an end.
But in my view, nothing is ever really banned by banning it.
Next time you catch yourself saying "it should be banned" reflect on whether you merely want it to ended, or whether you really wish it to perhaps continue but be subject to a criminal justice system processing unlucky future incidents of it ever being caught.