Professional mediators maintain that parties to a conflict have an incentive to enter serious negotiations only when they find the pain of continuing hostilities less bearable than the concessions needed to end it. The problem in Syria’s civil war, according to many diplomats, is that the regime of President Bashar al-Assad and the opposition have yet to reach a “mutually hurting stalemate”.

The problem with this theory is it does not specify who is hurt. The reality is that Syrian civilians are feeling more pain than the regime, while the Islamic State in Iraq and the Levant, the monstrous militant group that now styles itself Islamic State, is prospering.

Three and half years into the disastrous war, Isis has accomplished the nearly impossible trick of uniting all the opposing parties: the US, Europe, Iran, Russia, the various Lebanese factions, the new Iraqi government and, of course, Mr Assad. Syria’s president had been buying oil from the movement (accounting for a good part of its resources until it laid its hand on oil and gas wells in Iraq) but now ostentatiously bombs it to make sure he comes out on the right side of the new consensus.