Stochastic terrorism: From the halls of power to schoolyards

As I went on my nightly dog walk with a neighbor couple, the wife who is a dedicated fifth-grade teacher mentioned a troubling new problem at her school. She said the principal had told her of a new trend he was seeing — boys were being reported for threatening another with “I’ll shoot you,” not in play but with a tone that chilled her. It wasn’t roughhousing anymore, she said — it was an echo from somewhere darker.

Her husband introduced a term I’d never heard before: stochastic terrorism. He said it described the way inflammatory words from public figures could set off unpredictable acts of...