Like Mr Bush, Lyndon Johnson, America’s president at the time of the 1965 blackout, demanded a full investigation. He called in the defence ministry and the Federal Bureau of Investigation to take part in the inquiry. One of its main outcomes was the creation of the North American Electric Reliability Council, a New Jersey-based industry group that works to ensure reliable service on the 500,000 miles of high-voltage power lines across North America. But as demand for electricity has grown, the council has found it increasingly hard to maintain the transmission system. Indeed, industry experts have been warning for some years that it is creaking under the weight of ever-heavier power loads. And the problem continues to get worse: the Electric Power Research Institute, based in Palo Alto, California, estimates that demand for power in America has grown at twice the rate at which transmission capacity has increased in the past decade. The rapid growth of power-thirsty air conditioning systems has played a big part. “We’re a superpower with a third-world grid. We need a new grid,” Bill Richardson, the governor of New Mexico and a former federal energy secretary, told CNN. “The problem is that nobody is building enough transmission capacity.”