Nikolas Cruz was dropped off by an Uber driver just outside the Marjory Stoneman Douglas High School in Parkland, Florida, on 14 February 2018. Carrying a rifle bag and backpack, he walked purposefully into Building 12 of the school, which contained 30 classrooms and about 900 pupils and 30 teachers. After activating a fire alarm, he used his AR-15-style semiautomatic rifle and fired indiscriminately. In six minutes he killed 17 people and wounded the same number before leaving the school grounds. It was the deadliest high school shooting in US history – but it is only one of many gun massacres where ten or more people were killed, as we see in Table 2.1.

For virtually anyone who lives outside the US, it is not just the fact of the massacre and others like it that they find incredible, but also the response to such atrocities by the authorities and large numbers of citizens. It is not only the vapidly proffered thoughts and prayers – the usual response of many politicians, a knee-jerk reaction condemned by Emma González, a surviving Parkland student – but where they place the blame. The local newspaper blamed the school for not responding quickly enough to the events. Politicians blamed local law enforcement for not responding rapidly and appropriately. Others blamed the fact that Cruz had not been properly supervised, or even locked up, because of his behavioural and psychological problems. Few questioned whether these very problems made him unfit to purchase a military-style assault weapon. The National Rifle Association (NRA), for example, had earlier supported President Trump's attempt to overturn an Obama-administration rule that required the Social Security Administration to provide information on mental health disorders during background checks on those attempting to buy guns.

What were some of the major positive responses of leading US politicians to the crime? President Trump proposed that arming and training up to 20 per cent of teachers to deal with terrorists would solve the problem. He also suggested that gunfree schools were a magnet for criminals; rather, guns should be carried in schools as a norm.