The triumph of the Islamic insurgency that ousted Syria’s dictator-for-life Bashar al-Assad resulted not only from the weakness of  Syria’s own army but also the unwillingness of allies Iran, the Lebanese militia Hezbollah and Russia to help in an hour of need.

A decade ago, those three allies aided Assad in fighting off an armed uprising by an eclectic group of rebels that emerged out of the Arab Spring civil protests that had swept across the Middle East. With the help of Russian air power and Lebanese ground forces supported by Iran, Assad eventually and brutally drove armed Syrian rebels into a zone in the nation’s far northwest.

Fast forward to the present, only one of those allies was in a position to help Assad counter the latest rebel blitz. But they only offered token help and it was all too little, way too late:

• Iran, which heads what it had called a regional “Axis of Resistance” but which is now engaged in a proxy war with Israel, had recently been bruised by Israeli rocket attacks. Tehran told Assad that it would only send some drones and rockets to protect the Syrian leader’s government...