This is true. But it misses something. In rejecting Nutt’s advice, Johnson is pandering to a large chunk of public opinion. Which raises the question: why is it that public opinion is more supportive of drug laws than the evidence would warrant? Here, I suspect, are the relevant cognitive biases:
1. The fear of the unknown. Most of the supporters of criminalizing drugs have, I suspect, not actually taken them; I’m excluding newspaper editors and journalists here. And people are naturally scared of the unfamiliar - hence the Frankenstein complex and (a few years ago) the fear of GM foods.
2. The status quo bias. People prefer existing evils to unfamiliar ones. For this reason, Nutt’s point that cannabis or ecstasy is less harmful than nicotine falls on deaf ears simply because, as Laban says, we’ve been smoking for 400 years but doing Es for barely 20.
3. Representative heuristic and ignorance of unintended consequences. Having decided that drugs are evvviiilll, people think that a policy of cracking down on drugs is somehow associated with less use of drugs - they think outcomes must somehow resemble inputs. What they don’t appreciate so much are the adverse effects of such laws: the gang wars as dealers fight for the high profits caused by restrictions on supply; the diversion of police time; the higher crime as addicts must steal more to pay higher prices.
Here, though, comes a problem. At least one recent opinion poll shows that these biases are not universal and that majority opinion - just - favours some legalization of drugs.
Which raises a depressing possibility. It seems that when public opinion is wrong - for example on immigration - politicians pander to it, but when it is right they ignore it. The function of representatives in representative democracy, it seems, is take all the idiocies of public opinion, and when these are insufficient, to then add some of their own.