Scroll through any social media platform long enough and you’ll notice something that doesn’t quite add up. The same talking points, phrasing, and sudden outrage cycles are appearing across completely different audiences at the same time. It feels coordinated. And that’s because it often is. Foreign adversaries have turned modern technology into a new kind of warfare, one the United States hasn’t fully named, hasn’t clearly assigned ownership of, and isn’t yet equipped to fight at the speed it’s being waged. This is something more insidious than traditional espionage: the deliberate, systematic manipulation of how millions of Americans perceive reality—their...