So far as the West and its allies are concerned, the Turks’ revival of hostilities against the Kurds is unhelpful for several reasons. The PKK, the most militant of the Kurdish groups, is rightly condemned as a terrorist organisation by Washington and other Western powers. But it is also closely allied with Syrian-based Kurdish groups which have proved to be the most effective fighters on the ground against Isil. Indeed, many of the bombing missions those newly-arrived American F-16s will be carrying out are expected to be in support of Kurdish operations on the ground in Syria against Isil. No wonder PKK leaders have accused Ankara of attacking Kurdish positions simply in order to protect their erstwhile allies in Isil.