I know all right-thinking people are supposed to be delighted that Colorado has legalised cannabis, the first American state to do so.
We are supposed to say: "When, oh when, will our government realise it is losing the war on drugs and should take a lesson even from Americans, who can be surprisingly liberal sometimes?"
But let us pause here for a moment.
The idea that the existing policy on drugs in this country – and almost everywhere in the world apart from Colorado and, er, Uruguay – is a self-evident failure is not a truth that is self-evident (to me, at any rate).
In particular, the 'war on drugs' and the notion that it is somehow being 'lost', is a tired cliche that helps to shut down thought rather than encourage it.
Illegal drug use in this country has decreased, is decreasing and ought to decrease further.
In particular, young people here drink less alcohol, smoke less tobacco and use fewer illegal drugs than they did.
Those are good trends. If the Government is waging a war on drugs, then it is winning it.
People who want to legalise drugs talk a lot about 'harm reduction' – and they are right to do so.
Let us then, while we are pausing, ask two questions.
One: is cannabis harmful?
Mostly, no. Mostly, its effect is to make people boring. But it is possible that, in some cases, it acts as a trigger for serious mental illness, especially for male teenagers.
Whether cannabis has been shown to be a trigger for people who are susceptible, or whether such people tend to try cannabis, is disputed and the proportion of people who might be susceptible is small.
But it would seem an unwise idea to do anything that might encourage more people to try cannabis unless we are absolutely sure.
So, the next question is whether legalising cannabis would lead to more young people trying it?
Well, what do you think?
It is at this stage supporters of legalisation tend to drive the argument into the bowling-alley gutters by saying: "What about the harm done by alcohol?"
It is serious, is the answer to that. And it is certainly more serious, on aggregate, than the harm done by cannabis.
But that is an attempt to change the subject. Do something about attitudes to alcohol, by all means. Rush out and buy Alastair Campbell's much-admired novel, My Name Is.
Give up for January. Or give it up for life. But none of this answers the question about how to minimise the harm of cannabis.
Then there is the harm done by the control of the production and supply of drugs by criminals.
Yes, it is a problem.
But we are mainly talking about cocaine and heroin, if we mean organised crime and drugs and a lot of the harm in those cases is suffered in Colombia and Afghanistan.
I don't have the answers to that; but, then, neither do the advocates of legalising cannabis, who tend not to propose legalising 'harder' drugs just yet. Finally, legalisers sometimes say that it is jolly confusing that cannabis is illegal in theory, but that the police tend to concentrate on more important things in their day-to-day practice.
It's a compromise.
It is so sensible that it is the most common legal position all over the world: illegal, but not stringently enforced for small amounts.
It is intellectually unsatisfactory, but it is winning.
The people who want to change it have to make a better case.