The notion that national security will one day be invoked to silence dissent comes as no surprise to hardened Hong Kongers. Commentators, academics and filmmakers have long prophesied that doomsday scenario. The writing has been on the wall for years, and the arrival of an anti-subversion law is a matter of when, not if. We just didn’t think it would happen so soon, at least not before the return of Article 23 that the city has fought so hard to keep at bay. But that day is now upon us.