On a recent Thursday morning in suburban Detroit, a man drove a pickup truck loaded with explosives through the front entrance of Temple Israel, the largest Reform synagogue in the United States.

Inside, were more than 100 young children under the age of five. The vehicle smashed through barricades and concrete, racing down a hallway before becoming lodged in the twisted wreckage. The driver began shooting. Security personnel returned fire, and staff moved quickly to evacuate the children, as smoke filled the building from the truck’s engine compartment.