Barack Obama is unlikely to have much trouble mustering a Nato coalition of the willing if Washington opts for military intervention in Syria in response to the alleged chemical weapons atrocities by the Assad regime.

There is, however, no prospect of a UN mandate for international military action over Syria – with the Kremlin, enraged at what it saw as abuse of a UN mandate to topple Muammar Gaddafi in Libya, certain to keep wielding its veto.