Ted Koppel is the author of “Lights Out,” which warns of a catastrophic cyber attack that could leave as much as a third of the nation without electricity for months or even a year. There is no government plan to respond to such an attack, he says. He says cyber attacks are a modern version of the balance of terror that each adversary has the capacity to destroy the other. He asks: Who needs nukes if a few keystrokes on a laptop could do as much or more damage?”]