3 June 2017 – By Andrew J. Tabler – FOREIGN POLICY – The game for who will rule eastern Syria after the Islamic State (or ISIS) is on. On May 18, the United States destroyed a military convoy allied with Syrian President Bashar al-Assad after it ignored repeated warnings to stop its advance on al-Tanf, a U.S. and British special operations base on the Syrian-Jordanian border. The base is covered under the October 2015 U.S.-Russian deconfliction agreement, which established a hotline for avoiding direct military confrontation between Russian- and U.S.-backed forces in Syria. This came a few days after the Russian base at Khmeimim had declared that its air force, along with Iranian military advisers, would support Assad’s troops in their attempt to push east, clearing the road from Damascus to Baghdad and preventing the formation of a U.S.-supported buffer zone in eastern Syria. All of this followed Washington’s announcement on May 9 that it would provide heavier weapons to the Kurdish factions of the Syrian Democratic Forces (SDF) to help them take ISIS’ capital, Raqqa—enraging U.S. ally Turkey.
Such actions are nominally about fighting ISIS. But the various actors in Syria are increasingly thinking about what comes next, with an eye toward the weaknesses of the other side. U.S.-Russian deconfliction agreements in Syria may soon be put to the test, increasing the likelihood of accidents at best. There is now a greater risk that the United States and its allies will be brought into direct military confrontation not only with Assad but with his Russian and Iranian backers—a risk that was previously tempered by the need of both factions to fight ISIS. To ensure that the risk of military confrontation remains manageable, the United States and Russia should agree on the parameters of a de-escalation zone in southern Syria that keeps the focus on ISIS and contains Iran’s ambitions for a land bridge through Syria to the Mediterranean. As things are going, however, this is unlikely to occur anytime soon,