Americans are determined that massacres such as happened in Newtown, Conn., never happen again. But how? Many advocate more effective treatment of mentally-ill people or armed protection in so-called gun-free zones. Many others demand stricter control of firearms.

We aren't alone in facing this problem. Great Britain and Australia, for example, suffered mass shootings in the 1980s and 1990s. Both countries had very stringent gun laws when they occurred. Nevertheless, both decided that even stricter control of guns was the answer. Their experiences can be instructive.

In 1987, Michael Ryan went on a shooting spree in his small town of Hungerford, England, killing 16 people (including his mother) and wounding another 14 before shooting himself. Since the public was unarmed—as were the police—Ryan wandered the streets for eight hours with two semiautomatic rifles and a handgun before anyone with a firearm was able to come to the rescue.

Nine years later, in March 1996, Thomas Hamilton, a man known to be mentally unstable, walked into a primary school in the Scottish town of Dunblane and shot 16 young children and their teacher. He wounded 10 other children and three other teachers before taking his own life.