The Syria conflict, now in its eighth year, remains a significant policy challenge for the United States. U.S. policy toward Syria in the past several years has prioritized counter terrorism operations against the Islamic State (IS, also known as ISIL/ISIS), but also has included nonlethal assistance to opposition-held communities, support for diplomatic efforts to reach a political settlement to the civil war, and the provision of humanitarian assistance in Syria and surrounding countries affected by refugee outflows. The counter-IS campaign works primarily “by, with, and through” local partners trained, equipped, and advised by the U.S. military, per a broader U.S. strategy initiated by the Obama Administration and modified by the Trump Administration. The United States also has advocated for a political track to reach a negotiated settlement between the government of Syrian President Bashar al Asad and opposition forces, within the framework of U.N.-mediated talks in Geneva.

In November 2017, Brett McGurk, Special Presidential Envoy for the Global Coalition to Counter ISIS, stated that the United States was entering a “new phase” in its approach to Syria that would focus on “de-escalating violence overall in Syria through a combination of ceasefires and de-escalation areas.” The Administration supported de-escalation as a means of creating conditions for a national-level political dialogue among Syrians culminating in a new constitution and U.N.-supervised elections. However, since mid-2017, the Asad government has retaken most opposition-held areas of Syria, including cease-fire and de-escalation areas. This appears to have significantly reduced pressure on the regime to make concessions to the opposition, with uncertain implications for the outcome of any future political dialogue. Meanwhile, U.S.-backed forces have since retaken most other areas formerly under IS control in eastern Syria.

Following an internal policy review, Administration officials in late 2018 have described U.S. policy towards Syria as seeking (1) the enduring defeat of the Islamic State; (2) a political settlement to the Syrian civil war; and (3) the withdrawal of Iranian-commanded forces. Administration officials have also stated that the United States will not contribute to reconstruction in Asad-held areas unless a political solution is reached in accordance with U.N. Security Council Resolution 2254. Questions remain about the extent to which U.S. forces might remain in Syria and specific U.S. assistance plans. The Administration has ended non-humanitarian U.S. support to opposition-controlled northwest Syria and has obtained foreign contributions to enable the reprogramming of U.S. funds that Congress appropriated to stabilize areas liberated from the Islamic State. The FY2019 National Defense Authorization Act (P.L. 115-232) requires the Administration to clarify its Syria strategy and report on current programs in order to obligate FY2019 defense funds for train and equip purposes in Syria.

To date, the United States has directed more than $8.6 billion toward Syria-related humanitarian assistance, and Congress has appropriated billions more for security and stabilization initiatives in Syria and in neighboring countries. The Defense Department has not disaggregated the costs of military operations in Syria from the overall cost of the counter-IS campaign in Syria and Iraq (known as Operation Inherent Resolve, OIR), which, as of June 2018, had reached $26.2 billion. President Trump requested $15.3 billion in additional FY2019 defense funding for OIR. Congress continues to consider proposals to authorize or restrict the use of force against the Islamic State and in response to Syrian government chemical weapons attacks, but has not enacted any Syria-specific use of force authorizations.

Looking forward, Congress may consider the purpose, scope, authorization, and duration of the U.S. military presence in Syria, the U.S role in ensuring a lasting defeat for the Islamic State and other extremists, U.S. investments and approaches to post conflict stabilization, the future of Syrian refugees and U.S. partners inside Syria, and the challenges of dealing with the Iran- and Russia-aligned Asad government.


In March 2011, antigovernment protests broke out in Syria, which has been ruled by the Asad family for more than four decades. The protests spread, violence escalated (primarily but not exclusively by Syrian government forces), and numerous political and armed opposition groups emerged. In August 2011, President Barack Obama called on Syrian President Bashar al Asad to step down. Over time, the rising death toll from the conflict, and the use of chemical weapons by the Asad government, intensified pressure for the United States and others to assist the opposition. In 2013, Congress debated lethal and nonlethal assistance to vetted Syrian opposition groups, and authorized the latter. Congress also debated, but did not authorize, the use of force in response to an August 2013 chemical weapons attack.

In 2014, the Obama Administration requested authority and funding from Congress to provide lethal support to vetted Syrians for select purposes. The original request sought authority to support vetted Syrians in “defending the Syrian people from attacks by the Syrian regime,” but the subsequent advance of the Islamic State organization from Syria across Iraq refocused executive and legislative deliberations onto counterterrorism. Congress authorized a Department of Defense-led train and equip program to combat terrorist groups active in Syria, defend the United States and its partners from Syria-based terrorist threats, and “promote the conditions for a negotiated settlement to end the conflict in Syria.”

In September 2014, the United States began air strikes in Syria, with the stated goal of preventing the Islamic State from using Syria as a base for its operations in neighboring Iraq. In October 2014, the Defense Department established Combined Joint Task Force-Operation Inherent Resolve (CJTF-OIR) to “formalize ongoing military actions against the rising threat posed by ISIS in Iraq and Syria.” CJTF-OIR came to encompass more than 70 countries, and has bolstered the efforts of local Syrian partner forces against the Islamic State. The United States also gradually increased the number of U.S. personnel in Syria from 50 in late 2015 to roughly 2,000 by late 2017. President Trump in early 2018 called for an expedited withdrawal of U.S. forces from Syria,1 but senior Administration officials have since stated that U.S. personnel will remain in Syria to ensure the enduring defeat of the Islamic State. National Security Advisor John Bolton has also stated that U.S. forces will remain in Syria until the withdrawal of Iranian-led forces.

U.S. and coalition-backed forces in Syria succeeded in retaking, from 2015 through mid-2018, nearly all of the territory once held by the Islamic State. Meanwhile, other outside actors (Lebanese Hezbollah, Iran, and Russia) continued to support the Syrian government’s military campaigns against opposition groups. Conflict between the coalition’s Syrian Kurdish partners and Turkey has further complicated the situation, as has the entrenchment of Al Qaeda-affiliated groups among the opposition and the ongoing humanitarian crisis. As of late 2018, more than 5.6 million Syrians have fled to nearby countries, with 5.8 million more internally displaced.

The collapse of IS and opposition territorial control in most of Syria since 2015 has been matched by significant military and territorial gains by the Syrian government. The U.S. intelligence community’s 2018 Worldwide Threat Assessment stated in February 2018 that, “The conflict has decisively shifted in the Syrian regime’s favor, enabling Russia and Iran to further entrench themselves inside the country.”2

The U.N. has sponsored peace talks in Geneva, but it is unclear when (or whether) the parties might reach a political settlement that could result in a transition away from Asad. With many armed opposition groups weakened, defeated, or geographically isolated, military pressure on the Syrian government to make concessions to the opposition has been reduced. U.S. officials have stated that the United States is committed to the enduring defeat of the Islamic State and will not fund reconstruction in Asad-held areas unless a political solution is reached in accordance with U.N. Security Council Resolution 2254.3 Congress is considering legislation that would condition the use of U.S. funds in Asad-controlled areas for non-humanitarian purposes and has directed the Administration to report to Congress on its strategy.


1.Remarks by President Trump on the Infrastructure Initiative, March 30, 2018; Remarks by President Trump and Heads of the Baltic States in Joint Press Conference, April 3, 2018.
2.Worldwide Threat Assessment of the U.S. Intelligence Community, February 13, 2018.
3.U.S. State Department, Briefing on the Status of Syria Stabilization Assistance and Ongoing Efforts to Achieve an Enduring Defeat of ISIS, August 17, 2018.