Jabhat al-Nusra, Ahrar al-Sham and their smaller allies seized the western city of Idlib on March 28 after a four-day offensive. The groups used multiple vehicle-borne improvised explosives to target key parts of the city's outer ring of defenses manned by loyalist forces. The attackers then carried out multi-directional attacks to exploit the gaps the bombings created in the loyalists' positions. They punched deep through two belts of defenses around the city before the loyalist forces could successfully respond and re-establish their defensive lines. The rebels are still conducting operations to eliminate the remaining pro-government forces, but the major fighting is finished — the Islamist rebels control the city.
Idlib is the capital and largest city in the northwestern province of the same name. It is the third provincial capital the government has lost after the Islamic State seized Raqaa to the east and rebel groups took Quneitra to the south. The city's fall comes at the end of a long period of consolidation by Jabhat al-Nusra and its Ahrar al-Sham allies in Idlib province, where they scored large victories against the Syrian military, such as the seizure of the major military bases around Maarat al-Nuaman. Jabhat al-Nusra has also driven out a number of more moderate U.S.-backed rebel forces such as the Syria Revolutionaries Front and Harakat Hazm.
Over the course of these operations, Jabhat al-Nusra and Ahrar al-Sham have proven themselves to be competent militant organizations capable of not only planning and executing fairly sophisticated offensives against well-defended enemy positions, but also of continuing their advances despite significant leadership losses. Indeed, the ability to seamlessly continue operations after losing combat leaders is vital for these organizations, given the typically high casualty rate among the military commanders who invariably lead directly from the front.
Over time, both organizations have also become more competent in the use of heavy weaponry, particularly the armored vehicles they seized from government forces. Instead of using them as armored pillboxes in defensive positions or simply as independent mobile artillery as they had done before, Jabhat al-Nusra, Ahrar al-Sham and other rebel factions not present in Idlib — such as Jaish al-Islam — have begun to combine their tanks into larger armored formations to carry out aggressive attacks with close infantry support. These tactics, in addition to the effective use of artillery fire and vehicle-borne improvised explosive devices, have been key to rebel successes against well-defended enemy positions.
By taking Idlib, Jabhat al-Nusra and Ahrar al-Sham have cemented their status as some of the most competent armed factions in the Syrian civil war. This enhanced prestige will make absorbing smaller rebel factions easier, especially for Ahrar al-Sham, which has a less extreme ideology compared to Jabhat al-Nusra. Indeed, the group absorbed Suqour al-Sham in a landmark agreement March 22. As long as Ahrar al-Sham and Jabhat al-Nusra can avoid infighting and continue their close relationship, they should be able to maintain their considerable momentum and largely drive out the loyalist forces from the rest of Idlib province. Also, as Ahrar al-Sham continues to garner prominence on the battlefield, outside parties interested in shaping Syria's political landscape such as the United States will have to lean on Turkey and Qatar, the group's primary backers.
After clearing the remaining government-held centers in Idlib province, Jabhat al-Nusra and Ahrar al-Sham will be able to strike out in three directions: south toward the vital crossroads of Hama, northeast toward the crucial city of Aleppo and west toward the Alawite population base in Latakia province. Regardless of which course of action the groups decide on, the effects will reverberate across the country as the Syrian military rushes to respond to the new offensive.
The fall of Idlib is a stark reminder that, despite being the strongest of the armed factions, the Syrian military is far from able to secure a decisive victory to end the war. Furthermore, the victory by these two rebel factions also highlights the fact that, even if the United States achieves its policy objectives of defeating the Islamic State and bringing the al Assad government to the negotiating table, Washington will still have to figure out a way to deal with powerful Islamist and jihadist factions in Syria who may not share the same interests as the United States.