Introduction

The protracted struggle over Kobani, mere months after sweeping unabated into Iraq’s second largest city, Mosul, must be testing the Islamic State’s leadership. This variation in their course, matched by their variation in approach, appears to be the secret to Islamic State’s success in Syria and Iraq. Their adaptability has created a coveted synthesis of hierarchy and networking, weaving together a traditional chain-of-command with a complex web of alliances, understandings, and online supporters.

In the context of Islamic State's integrated military and governance framework, brigades are a key mobile component of IS adaptability, the secret to Islamic State’s success in Syria and Iraq. The Islamic State's ability to maintain control of it's territory has much to do with how these brigades are utilized differently on a state-by-state and town-by-town basis. The "vertical" and "horizontal" relationships of brigades explain how the Islamic State has become so successful and it are essential for combating the group's two-state insurgency.