Wall Street Journal: The U.S. could suffer a coast-to-coast blackout if saboteurs knocked out just nine of the countrys 55,000 electric-transmission substations on a scorching summer day, according to a previously unreported federal analysis. The study by the Federal Energy Regulatory Commission concluded that coordinated attacks in each of the nations three separate electric systems could cause the entire power network to collapse, people familiar with the research said. A small number of the countrys substations...