For anyone interested in the policing of the world’s shipping lanes, or just in war tech, this short film above the fold on the WSJ’s home page is a must-watch. It’s about an uncrewed US military mini-sub called the Triton which can raise a rigid wing-like sail, lower it to dive, and stay at sea for three months at a time. It can sink ships as well as spy on them, but it doesn’t need human supervision even to tell it when to dive. On-board computers assess any threats and can do that thinking by themselves. We’re told the US is already using the Triton to keep an eye on Iranian maritime movements – presumably in the Gulf – but its maker, a Mississippi firm called Ocean Aero, has just visited Taiwan with a view to selling dozens of drone subs to help deter a Chinese invasion for which Xi Jinping wants his forces to be ready by 2017. Two questions: when will war become a pure battle of machines with no human lives at stake? Also, how can news organisations make videos about military hardware feel less like ads?