The world over, mass shootings are frequently met with a common response: Officials impose new restrictions on gun ownership. Mass shootings become rarer. Homicides and suicides tend to decrease, too.
After a British gunman killed 16 people in 1987, the country banned semiautomatic weapons like those he had used. It did the same with most handguns after a 1996 school shooting. It now has one of the lowest gun-related death rates in the developed world.
In Australia, a 1996 massacre prompted…
