What began as protests against President Assad’s regime in 2011 quickly escalated into a full-scale war between the Syrian government—backed by Russia and Iran—and anti-government rebel groups—backed by the United States, Saudi Arabia, Turkey, and others in the region. Three campaigns drive the conflict: coalition efforts to defeat the Islamic State, violence between the Syrian government and opposition forces, and military operations against Syrian Kurds by Turkish forces.
The Islamic State began seizing control of territory in Syria in 2013. After a series of terrorist attacks coordinated by the Islamic State across Europe in 2015, the United States, the United Kingdom, and France—with the support of Turkey, Saudi Arabia, and other Arab partners—expanded their air campaign in Iraq to include Syria. Together, these nations have conducted over eleven thousand air strikes against Islamic State targets in Syria, while the U.S.-led coalition has continued its support for ground operations by the SDF. Turkish troops have been involved in ground operations against the Islamic State since 2016, and have launched attacks against armed Kurdish groups in Syria. Meanwhile, at the request of the Syrian government in September 2015, Russia began launching air strikes against what it claimed were Islamic State targets, while Syrian government forces achieved several notable victories over the Islamic State, including the reclamation of Palmyra. According to the U.S.-led coalition against the Islamic State, 98 percent of the territory formerly held by the group in Iraq and Syria, including Raqqa and Deir al-Zour, has been reclaimed by Iraqi security forces and the SDF.
With Russian and Iranian support, the Syrian government has steadily regained control of territory from opposition forces, including the opposition’s stronghold in Aleppo in 2016. The regime has been accused of using chemical weapons numerous times over the course of the conflict, resulting in international condemnation in 2013, 2017, and 2018. Opposition forces have maintained limited control in Idlib, in northwestern Syria, and on the Iraq-Syria border.
Efforts to reach a diplomatic resolution have been unsuccessful. Geneva peace talks on Syria—a UN-backed conference for facilitating a political transition led by UN Special Envoy Staffan de Mistura—have not been successful in reaching a political resolution, as opposition groups and Syrian regime officials struggle to find mutually acceptable terms for resolving the conflict. A new round of peace talks began in Geneva in May 2017 with an eighteen-person delegation from Syria but has since stalled. Also in 2017, peace talks initiated by Russia in Astana, Kazakhstan, with Iran, Turkey, and members of Syria’s government and armed opposition leaders resulted in a cease-fire agreement and the establishment of four de-escalation zones. However, shortly after the cease-fire was announced, attacks by Syrian government forces against rebel-held areas in the de-escalation zones resumed.
According to estimates by the United Nations, more than 400,000 people have been killed in Syria since the start of the war. The UN reports that, as of January 2019, more than 5.6 million have fled the country, and over 6 million have been internally displaced. Many refugees have fled to Jordan and Lebanon, straining already weak infrastructure and limited resources. More than 3.4 million Syrians have fled to Turkey, and many have attempted to seek refuge in Europe.
Meanwhile, external military intervention—including the provision of arms and military equipment, training, air strikes, and even troops—in support of proxies in Syria threatens to prolong the conflict. Outside actors—namely Iran, Israel, Qatar, Russia, Saudi Arabia, Turkey, and the U.S.-led coalition—increasingly operate in proximity to one another, complicating the civil war and raising concerns over an unintended escalation. Ongoing violence and proxy conflicts could also facilitate the resurgence of terrorist groups.
In December 2018, President Donald J. Trump announced a decision to withdraw the roughly two thousand U.S. troops remaining in Syria. On January 16, 2019, an attack in Manbij claimed by the self-proclaimed Islamic State killed at least nineteen people, including four Americans. Prior to that attack, only two Americans had been killed in action in Syria since the U.S.-led campaign began. The U.S.-led international coalition continues to carry out military strikes against the Islamic State and provides support to the Syrian Democratic Forces (SDF) and internal security forces.
The pullout of U.S. troops has increased uncertainty around the role of other external parties to the conflict—including Iran, Israel, Russia, and Turkey—as well as the future of internal actors.