If nothing has happened yet, why would anything happen now? Five years ago in Sandy Hook, 27 students and teachers were shot dead. Two years ago in Orlando, 49 people were shot dead in a nightclub. Five months ago in Las Vegas, 58 were shot dead at a music festival. None of these incidents — and this is not, of course, a comprehensive list of recent mass shootings in the US — was followed by significant national gun legislation.

If these atrocities did not inspire change, the easy conclusion is that the death of 17 students and teachers in Parkland, Florida, last week will not lead to new laws, either. The US, on this view, has collectively decided that more than 30,000 gun deaths a year — a rate many times higher than the rest of the developed world — is a price worth paying for unrestricted access to firearms. The deaths will continue because they are rooted in US gun culture.

Such a conclusion, while tempting, is wrong. America does have a gun culture, but cultures are not immutable. In other areas — race relations, for example — cultural changes over the past half century have been immense. And there are signs of cultural change on firearms: the proportion of US households that own guns has decreased significantly in recent decades. While national legislative change has been minimal, the funding and organisation of gun control groups, such as the Brady Campaign and Moms Demand Action, is improving.