The Download: war in Europe, and the company that wants to cool the planet

Plus: Amazon has listed retailers' goods without their permission Last spring, 3,000 British soldiers deployed an invisible automated intelligence network, known as a "digital targeting web," as part of a NATO exercise called Hedgehog in the damp forests of Estonia's eastern territories. The system had been cobbled together over the course of four months--an astonishing pace for weapons development, which is usually measured in years. Its purpose is to connect everything that looks for targets--"sensors," in military lingo--and everything that fires on them ("shooters") to a single, shared wireless electronic brain. Eighty years after total war last transformed the continent, the Hedgehog tests signal a brutal new calculus of European defense. But leaning too much on this new mathematics of warfare could be a risky bet. This story is from the next print issue of magazine.