Since Islamic State (IS) first swept through Mosul and large swathes of northern Iraq in June, the militant group has been careful to avoid direct confrontation with Iraqi Kurdistan’s Peshmerga forces; even allowing them to move into the long-disputed city of Kirkuk and hold onto it relatively unopposed. This early deference on the part of IS may have stemmed from the Peshmerga’s reputation as a highly organized and battle-hardened force, or simply from the hope that Kurdish authorities would respond to the initial IS advance by abandoning Baghdad in deed and perhaps even word via a declaration of independence. Either way, this unwritten understanding between them disintegrated last week when IS forces made a push towards Erbil on multiple fronts, a push that – much to many analysts’ surprise – was successful in driving Peshmerga forces from several towns on the periphery of the Kurdistan region, as well as the Mosul dam. IS fighters even managed to capture Gwer and Makhmur, cities within about an hour’s drive from Erbil. They have since been re-captured by the Peshmerga.