The battle for Raqqa, the Islamic State's self-declared capital in Syria, has begun. The Syrian Democratic Forces (SDF) are advancing toward the city, engaging the jihadist group in the villages of al-Hisha, Tal Samen and Mutamshirij along the way. Because of Raqqa's strategic importance, the Islamic State will do everything in its power to keep the city within its grasp. Driving the militants from their stronghold will not be easy or cheap, but if the SDF is successful, it will greatly accelerate the Islamic State's defeat in Syria.
For the Islamic State, the loss of Raqqa would be a devastating blow. The city has symbolic value as the capital of the group's so-called caliphate; it is also an important hub for transporting people and supplies. Raqqa sits on the Euphrates River and is the key to controlling several critical highways in Syria. Without it, the Islamic State would have a much harder time moving fighters and goods from Aleppo province to eastern Syria and beyond. Instead it would be forced to rely on the Resafa-Ash Shola road, which is increasingly threatened by the Syrian government's advances toward Deir el-Zour.
Given the city's significance to Islamic State operations in Syria, the group can be expected to funnel substantial resources and reinforcements toward its defense. In addition to sending more fighters to Raqqa, the Islamic State will likely launch counterattacks along the SDF's other front lines, including al-Hasaka, in an effort to distract its foe. However, the Islamic State will be at a disadvantage: While the SDF is focusing most of its attention on attacking the jihadist group, the Islamic State has to contend with the Syrian rebels, Syrian government troops, Kurdish peshmerga and Iraqi forces. Devoting additional attention and resources to Raqqa when it is already overstretched will inevitably hurt the extremist group elsewhere on the battlefield.