This fixation on stopping bad things — as opposed to stopping bad people or bad behavior — goes beyond keeping air travel safe from al-Qaeda. On the international stage, it shows up in campaigns to reduce strategic arsenals and destroy nuclear warheads, regardless of the moral caliber of the governments possessing them. …

More recently, the shrill demands for more restrictions on guns in the wake of the Newtown massacre have been a classic illustration of the phenomenon. …

It is fundamental to the Judeo-Christian outlook that human beings are not naturally good. “The intention of man’s heart,” God says in Genesis, “is evil from his youth.” To use the Christian formulation, man is “fallen.” All of us are tugged by conflicting moral impulses, and whether we do the right thing or the wrong thing is up to each of us.

Peace, justice, and compassion are not the natural human condition. With rare exceptions, criminal violence can’t be blamed on external culprits. Murder isn’t caused by poverty or gory videogames or low self-esteem – or guns. Nor are wars caused by nuclear missiles, or al-Qaeda terrorism by box cutters. We fool ourselves if we imagine that by fixating on missiles and box cutters we can avoid reckoning with the cruel side of human nature.