The grid is under attack

On the evening of December 3, the lights went out in Moore County.

For tens of thousands of central North Carolina residents among the Piedmont hills west of Fayetteville, electric heaters became useless against the cold, the internet went dead, and refrigerator fans spun to a halt. Traffic lights went dark at intersections and cell phone batteries began to dwindle. Local authorities declared a state of emergency and, fearful of potential unrest, enforced a curfew.

The outage was no accident: Attackers had rained gunfire on two electrical substations, the facilities...