Forever War

On May 22, Salman Abedi, 22, waiting at the entrance of the Arianna Grande pop concert in Manchester, blew himself up, killing almost two dozen people, among them parents waiting to pick up their children.

Saturday, three Islamic terrorists committed “suicide-by-cop,” using a van to run down pedestrians on London Bridge, and then slashing and stabbing patrons of pubs and diners in the nearby Borough Market.

By all accounts, the killers bore no special grudge against those they murdered. They...