The initiatives announced by the United States government in view of limiting and controlling the diffusion and use of arms are certainly a step in the right direction. It is estimated that Americans today possess about 300 million firearms. No one can be under the illusion that limiting their number and use would be enough to impede horrendous massacres in the future, such as the one in Newtown, which shook the conscience of Americans and of the world, of children and adults alike.

But it would be much worse if we were to satisfy ourselves with only words. And if the massacres are carried out by people with mental illness or distorted by hate, there is no doubt that they are carried out with arms. Forty-seven religious leaders of various confessions and religions have...