US President Obama’s famous ‘red line’ speech relating to use of chemical weapons in Syria by the Assad regime in 2012, sparked off a debate among etymologists as to the exact origin and meaning of ‘red line’. As a boundary or limit beyond which the actions of another state, nation or organisation will not be tolerated, ‘red line’ seems to date from the 1980s when it was first used to describe actions between Libya and Chad. Then in 1999, The New York Times reported that Iran had set out ‘a red line for their revolution that no one should cross’. As a phrase, red line seems to be confused with a much older concept, namely to draw a line in the sand, which actually means the same sort of thing. Infamously, however, Obama’s red line proved to be a moveable feast in that it failed to deter the Assad regime in Syria from using chemical weapons and therefore was not really a ‘red line’ at all.