Eleven years ago, al-Qaeda terrorist Richard Reid tried to blow up American Airlines Flight 63 with a bomb hidden in his shoes. As a result, air travelers to this day must remove their shoes to pass through security at US airports.

In 2006, terrorists plotted to destroy as many as 10 planes flying from London to North America using peroxide-based liquid explosives smuggled in their carry-on luggage. So passengers now must limit any liquids they carry through security checkpoints to minuscule containers sealed in clear plastic bags.

On Christmas Day in 2009, Umar Farouk Abdulmutallab tried to blow up a Northwest Airlines flight over Detroit by means of an explosive device sewn into his underwear. The government’s response: full-body X-ray scans to detect even contraband concealed in one’s groin.

Our irritating, inconvenient airport security rules are one reflection of a common view that the way to prevent evil in this world – in this case, the evil of jihadist terrorism – is to intercept the instruments evildoers use. Thus, if the 9/11 hijackers used box cutters to carry out their airborne atrocities, box cutters must be barred from subsequent flights. If other terrorists find other means of committing brutal acts, we bar those means as well.

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. In schools, zero-tolerance drug and alcohol policies have been applied so rigidly, USA Today observes, that “kids have been kicked out of school for possession of Midol, Tylenol, Alka Seltzer, cough drops, and Scope mouthwash.”

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.

For countless people, especially on the left, it’s axiomatic that Adam Lanza’s bloodbath was caused by America’s gun culture. Many angrily demonize guns and the advocates of gun rights; they are convinced that only an ignoramus or a moral monster could oppose tighter gun control. In an interview on CNN, Piers Morgan lashed out at the executive director of Gun Owners of America, calling him “an unbelievably stupid man” and seething: “You don’t give a damn, do you, about the gun murder rate in America?” When the National Rifle Association’s Wayne LaPierre argued for more armed security rather than fewer arms, he too was drenched with scorn.

“Look, a gun is a tool,” LaPierre said. “The problem is the criminal.” But that can only be true if crime is rooted in the bad character, depraved values, or evil choices of those who use guns to murder. And that can only be true if men and women, by and large, are not innately good and kind – if decent behavior, like monstrous behavior, is a matter of free choice, not a hardwired instinct.

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.

“It’s a wonder I haven’t abandoned all my ideals, they seem so absurd and impractical,” 15-year-old Anne Frank confided to her diary on July 15, 1944. “Yet I cling to them because I still believe, in spite of everything, that people are truly good at heart. I simply can’t build my hopes on a foundation of confusion, misery, and death.”

Three weeks after those heartbreaking words were written, the Gestapo discovered the secret annex where Anne and seven others had been hiding. She died in the Bergen-Belsen concentration camp the following March.

The desire to believe, like Anne Frank, that “people are truly good at heart” is powerful. Sadly, history refutes the idea that human nature alone will make a good world. Controlling bad things may sometimes be prudent. But it is above all by controlling ourselves – by fortifying the better angels of our nature – that the struggle against evil progresses.

(Jeff Jacoby is a columnist for The Boston Globe. His website is www.JeffJacoby.com).