Meanwhile Assad is being bolstered by Russia, the Kurds are being bolstered by the West and Shia Iraq is supported by Iran. All these alliances are progressively beating Isil back. The likely outcome is that from now on Isil will simply be eroded with a long war of attrition, until the group are no longer be able to recruit enough fighters to sustain its gains. At which point, it is likely it will collapse. It will not be easy, and it will not be pretty. But as things stand this is the direction in which the situation is heading.