For the Record': 'The Most Significant Incident of Domestic Terrorism' You May Never Have Heard Of

In April 2013, gunmen opened fire on a California power substation near San Jose. A total of 17 transformers were damaged at a facility that provides power to most of the Silicon Valley.

While local law enforcement called it an act of vandalism, the former chairman of the Federal Energy Regulatory Commission declared it, “the most significant incident of domestic terrorism involving the grid that has ever occurred.”

The incident received little media attention at the time, even though some viewed it as a possible precursor to an even more serious attack. More recently, someone cut two fiber optic cables in Livermore, California, near San Jose on Sept. 14. That followed a similar incident in the same town in July, when three fiber optic cables were cut, knocking out phone and TV service in the area. In all, there have been about a dozen such attacks in the region in the last year.

Are these incidents random acts, or could they be the operational blueprint designed to bring down major electrical grids in the United States? If so, experts say it could trigger a cascading failure across the entire U.S. power system that would leave millions of Americans fighting to survive.