The fight for Mosul is taking place in territories characterized by a patchwork of overlapping ethnic, religious and national identities. Kurdish forces have effectively extended their control over more northern oil fields with PM ‘Abadi apparently unwilling and unable to challenge them.

Iraq’s military offensive to liberate Mosul from the self-proclaimed Islamic State (IS), launched on 17 October, continues to grind forward, but in many ways the politics is already...