In recent years, there has been a welter of complaints among Americans about heavy-handed airport security procedures. Little wonder: since 2001, the US has heavily increased overall homeland security at a cost of more than $1,000bn – and one consequence has been endless airport X-ray machines, body scanners, CCTV cameras and “pat-downs”, which many Americans hate.

But these days I have quite a different reason to feel profoundly irritated with airline security. Last week, my hand luggage mysteriously vanished as it went through those X-ray machines in JFK. And, to my shock, I have subsequently discovered that there is no way of telling what happened, since “improved” CCTV only covers part of the airport.

Hence, I am not only feeling annoyed. I am also wondering afresh about the social and psychological impact of all these cameras. Has all that trillion-dollar security spending actually made us “safer”? Or do such elaborate screening rituals cause us to turn off our brains? And how do we define safety anyway, at a time when political candidates for the 2012 election keep bandying about the word “security”?