The other day l heard Sergei Lavrov explain Moscow’s backing for Bashar al-Assad’s murderous repression in Syria. Russia’s foreign minister, I admit, did not express it quite like that. A former career diplomat, Mr Lavrov is a clever man. He deployed all manner of casuistry to explain that, contrary to vicious western propaganda, Russia was acting in an entirely even-handed way. This was a journey back to the cold war.

The Russian veto at the UN Security Council – matched by China – has had the predictable and predicted effect. Mr Assad has redoubled the military assault on opponents of his regime, ignoring any distinction between civilians and armed rebels. The death toll is rising sharply. The Arab League’s effort to secure a negotiated transfer of power has receded further as Syria tips towards full-scale civil war.

There are many explanations for the veto. The Assad dynasty has been a strategic ally since Soviet times. Moscow (and Beijing) think they were tricked into accepting the UN vote that led to the removal of Libya’s Muammer Gaddafi. The Syrian port of Tartus is a vital Russian naval base. There are big arms contracts at stake. All these can be added to Moscow’s familiar doctrine of non-interference.