On April 20, 1999, in what turned out to be the worst school shooting in the nation’s history, students Eric Harris and Dylan Klebold opened fire on their classmates at Columbine High in Littleton, Colorado, killing twelve students and one teacher before committing suicide. Survivors of the massacre reported that the killers—apparently motivated by revenge—had laughed gleefully as they stalked and murdered their victims.

In the view of some commentators, the Columbine killings share a disturbing similarity with the 1995 movie The Basketball Diaries, in which the main character, played by Leonardo DiCaprio, is cheered on by friends as he guns down students who had taunted him. Columnist Terry Teachout states that “to watch that horrific clip is to know in your bones that Harris and Klebold must also have seen it at some point in...