Nearly a dozen Syrian rebel groups, predominantly associated with the Free Syrian Army, announced on Jan. 2 that they would no longer take part in talks to organize a peace conference in Astana, Kazakhstan, later this month, accusing loyalist forces of violating the latest cease-fire in the country's civil war. Specifically, attacks by government forces on Wadi Barada and in eastern Ghouta near Damascus seem to have persuaded rebel forces to take a harder stance. Some of the rebel groups have already violated the cease-fire in response, shelling loyalist positions Jan. 3 in Idlib and near Damascus.

Support for the cease-fire from Damascus, and to a large extent, Iran, is not robust. The halt in hostilities that began Dec. 29 was driven by Russia, a key loyalist ally, which is looking for an opening to end its involvement in the conflict. The support by Iran and the Syrian government for the truce came, in part, in response to the growing Islamic State threat in Homs province. From the Syrian government's perspective, a cease-fire could be a temporary measure that would allow its forces to focus on pushing the Islamic State away from the energy-rich areas that surround Palmyra.

Even so, Damascus and Tehran clearly had no intention of completely halting attacks on the rebels. Under the pretext of striking at areas held by Jabhat Fatah al-Sham, the loyalists maintained their offensives around Damascus (specifically in the eastern Ghouta and Wadi Barada areas, which are occupied primarily by rebels who are not part of Jabhat Fatah al-Sham) even as they largely curtailed their operations against that group's strongholds in the north.

For the Russians, the loyalist offensives around Damascus threaten to undermine its effort to develop an exit strategy from the Syrian conflict, despite Turkey's support for the truce. Even though Turkey wields considerable influence over the rebels, it cannot force them to maintain their commitment to a cease-fire while loyalist forces defeat rebel pockets piecemeal. Even given their extensive history of infighting, the rebels understand that they have no chance if Damascus has the opportunity to focus efforts in one area at a time.

To that end, the cease-fire effort, precarious at its inception, is already close to collapse, and if it does, so will the latest Russian effort to find an exit strategy from the Syrian conflict.