Not long after Donald Trump’s surprising presidential victory, an article published in the Swiss weekly Das Magazin, and reprinted online in English by Vice, began churning through the Internet. While pundits were dissecting the collapse of Hillary Clinton’s campaign, the journalists for Das Magazin, Hannes Grassegger and Mikael Krogerus, pointed to an entirely different explanation—the work of Cambridge Analytica, a data science firm created by a British company with deep ties to the British and American defense industries. According to Grassegger and Krogerus, Cambridge Analytica had used psychological data culled from Facebook, paired with vast amounts of consumer information purchased...