In the past week, the Islamic State seized the ancient city of Palmyra from Syrian President Bashar al Assad's forces. The city's capture adds to the many defeats Damascus has suffered over the past six months, compounding its problems as it faces threats on multiple fronts.
The Islamic State's victory in Palmyra is notable for two reasons. First, it has completely isolated loyalist forces in Deir el-Zour province, including the 137th Mechanized Brigade and the elite 104th Republican Brigade. Though these units could still receive supplies by air, the Syrian air force is heavily committed to other areas of the conflict. It would be nearly impossible for the government to adequately sustain the encircled forces over the long term. Second, Palmyra's location — a critical crossroads in the center of Syria — gives the Islamic State a strategic base from which it can launch attacks on key locations in the surrounding area. Because loyalist forces hold nearly all of the important targets in Palmyra's vicinity, the Islamic State's new advantage does not bode well for al Assad's overstretched forces.
The Islamic State's maneuvers in Homs province, where Palmyra is located, denote a shift in its strategy in Syria. Previously, the Islamic State fought against the People's Protection Units in Kobani and al-Hasaka while maintaining its positions in Aleppo province. However, in each of these areas the Islamic State has been subject to repeated U.S.-led coalition airstrikes, which have degraded its manpower and have compromised its ability to conduct successful operations.
Consequently, the Islamic State gradually devoted more of its fighters to battles against the Syrian government and rebel forces unattached to the Free Syrian Army. So far, the U.S.-led coalition has avoided striking Islamic State fighters operating near loyalist forces; it wants to dispel any notion that it supports the al Assad government. This trend has continued even in the face of the Islamic State's intensified attacks in Homs and Deir el-Zour provinces.
Earlier in the conflict, Damascus removed its forces from Homs province and deployed them against the growing rebel threat of Jaish al-Fateh in Idlib province. The redeployment, which transferred the elite Tiger Forces and Desert Falcons away from the Islamic State's area of operations, will now be seen as a mistake. The elite forces have been unable to halt rebel advances in Idlib, and their departure from Homs has left the government highly vulnerable on its eastern flank.
The Islamic State now threatens the Syrian government's core territory, which stretches from Damascus to Aleppo. Finding the forces needed to contain this threat will be difficult, since the territory in question is vast and covers different types of terrain. Instead, it is likely that the government will try to take the fight to Islamic State forces stationed in Palmyra, if not to recapture the city then to pin the group down in a single location and keep it from spreading to other strongholds. Either way, any action al Assad takes in response to the Islamic State's success in Homs will expose Damascus on other fronts.