Surveillance used to be expensive. Even just a few years ago, tailing a person’s movements around the clock required rotating shifts of personnel devoted full-time to the task. Not any more, though. Governments can track the movements of massive numbers of people by positioning cameras to read license plates, or by setting up facial recognition systems. Those systems need few people to operate them, automating the collection of information about people’s lives and adding that data to searchable databases. Surveillance has become cheap.