Beijing sees forces bent on weakening it everywhere: embedded in multinational companies, infiltrating social media, circling naïve students. And it wants its people to see them, too. Chinese universities require faculty to take courses on protecting state secrets, even in departments like veterinary medicine. A kindergarten in the eastern city of Tianjin organised a meeting to teach staffers how to “understand and use” China’s anti-espionage law. China’s Ministry of State Security, a usually covert department that oversees the secret police and intelligence services, has even opened its first social media account, as part of what official news media described as...