For instance, the reason for these murders cannot be that "America is a gun culture," because Americans have always owned a lot of guns. Yet American schoolchildren have not always been moved to commit indiscriminate slaughter.

What has changed, that could more plausibly explain this alarming phenomenon?

Tuesday's events bring to mind the famous episode of Richard Loeb and Nathan Leopold, two young men who, in 1924, conceived and executed the "perfect crime" --the murder of a schoolmate. They were caught, convicted and sentenced to life plus 99 years in prison. In his writings later, Leopold made plain this was an experiment-- "as easy for us to justify as an entomologist in impaling a beetle on a pin" --inspired by the philosophy of Friedrich Nietzsche.

By coincidence, and along the same lines, the following story was brought to my attention yesterday morning.

A viewer of an award-winning TV series recently e-mailed ABC Television, owned by Disney Co., criticizing the story line of an episode in which a lawyer's mother wanted him to help her obtain the right in court to marry another woman.  The lawyer's reluctance to do so was portrayed as backward and intolerant. The viewer's e-mail referred to the Bible in suggesting that this reluctance may instead have been correct.

Here is the response this viewer received from the ABC Online Webmaster: "How about getting your nose out of the Bible (which is only a book of stories compiled by many different writers hundreds of years ago) and read the Declaration of Independence (what our nation is built on) where it says 'All Men are Created Equal'--and try treating them that way for a change!?  Or better yet, try thinking for yourself and stop using an archaic book of stories as your crutch for your existence."

Let me make two rebuttal points to this startlingly frank (and intolerant) response that I think are relevant as we think about yesterday's school murders.

First, the principle of human equality in the Declaration of Independence is a moral, not a morally relativistic principle. It is a recognition that human beings have a common nature, that they are able to understand that nature by use of their reason, and that they are able to deduce from it common rules of morality, or what the Declaration calls "the laws of nature and of nature's God." One of these deductions is that humans are born male and female for the purpose of procreation and child-rearing.   Thus laws that restrict marriage and adoption to men and women are in keeping not only with the Bible, but with nature, and with the Declaration.

Second, the idea that it is better to "think for yourself" than to draw upon "archaic stories" such as the Ten Commandments, the Sermon on the Mount, or the Declaration's laws of nature, is an idea that has been common to every criminal since the dawn of time.  But since the 1960s it has been adopted as a maxim of American education and promoted as a truism by our popular culture.  This bodes ill.

In the wake of the events in Littleton, let us first pray for our country and for our families, and then let us stand strongly for the idea of liberty rooted in moral principle, not moral relativism.