Domestic Terrorists Could Take Out U.S. Power Grid—and Attacks Have Started

Most people ignore the electrical grid, until it stops working. When that happens, the disruption can be total, but most often is a matter of inconvenience—the lights go out, the internet goes down, there is no place to recharge a cell phone.

But what if power did not return for days, weeks or months? And what if such a lengthy blackout engulfed not just a neighborhood or a county but a wide swath of the nation? The consequences, experts say, would be devastating. Many people would have no water to...