It’s a messy, imperfect and sometimes slow-to-react system, but over time it has shown itself to work. Instinctively, the American public knows this to be true, which is why it has greeted Mr Snowden’s “revelations”, if that is what they are, with a collective “meh”. The majority do not fear lapsing into a surveillance state because they see no evidence of it. For all the paranoid fantasies of the liberal and libertarian fringes, people do not – as they do in China or Russia – disappear in the night, or have their careers ended or their businesses closed merely for disagreeing with Mr Obama or Mr Cameron.