The rise of the insurgent terrorist group known as the Islamic State (IS, aka the Islamic State of Iraq and the Levant or ISIL/ISIS) and Russia’s military intervention on behalf of the Syrian government have reshaped debates over U.S. policy toward the ongoing civil conflict in Syria, now in its fifth year. The Islamic State controls large areas of northeastern and central Syria, from which it continues to launch assaults on forces opposed to and aligned with the government of President Bashar al Assad. Meanwhile, fighting elsewhere pits government forces and their foreign allies against a range of anti-government insurgents, some of whom have received limited U.S. assistance. Russian military intervention in support of Assad poses a direct challenge to U.S. goals in Syria, and is raising new questions about the future of the conflict and U.S. strategy.

Since March 2011, the conflict has driven more than 4.1 million Syrians into neighboring countries as refugees (out of a total population of more than 22 million). More than 7.5 million other Syrians are internally displaced and are among more than 12 million Syrians in need of humanitarian assistance. The United States remains the largest bilateral provider of such assistance, with more than $4.5 billion in U.S. funding identified to date. The United States also has allocated more than $440 million to date for nonlethal assistance to select opposition groups, and President Obama requested $385 million in FY2015 and FY2016 Overseas Contingency Operations (OCO) funding for such assistance. The $600 million FY2016 defense request for the Syria Train and Equip program may support a planned shift in the program toward equipping vetted units in Syria. The Administration also seeks more than $1.6 billion in Syria-related FY2016 humanitarian aid and refugee response funds.

Syrian officials and their Russian and Iranian backers have stated their conditional willingness to serve as “counterterrorism” partners of the United States in Syria, provided that U.S. officials accept a role for the Assad government as a bulwark against Sunni Islamist extremism. However, the Obama Administration and several Members of Congress have rejected the prospect of partnership with Assad, as well as his characterization of all of his opponents as “terrorists.” U.S. officials have described a “fundamental strategic disagreement” with Russia over its military intervention and Assad’s future, and they continue to call for a managed political transition and describe Assad as having lost legitimacy. Some Members of Congress and observers have argued that the United State should seek to compel Assad or act militarily to protect Syrian civilians. Others have expressed concern that disorderly regime change could further empower extremists or that civilian protection missions could prolong the conflict or involve the United States and its partners too deeply in stabilizing Syria over the long run.

U.S. officials and Members of Congress continue to debate how best to pursue U.S. regional security and counterterrorism goals in Syria without inadvertently strengthening Assad, the Islamic State, or other anti-U.S. armed Islamist groups. Anti-Assad armed forces and their activist counterparts have improved their coordination in some cases and share antipathy toward Russia’s intervention, but they remain divided over tactics, strategy, and their long-term political goals. Powerful Islamist forces seek outcomes that are contrary in significant ways to stated U.S. preferences for Syria’s political future. The United Nations Security Council has endorsed new efforts at negotiation and has created a new body empowered to assign responsibility for the use of chemicals as a weapon of war in Syria

The 114th Congress is now considering proposed appropriations (H.R. 2685, S. 1558, and H.R. 2772) and authorization legislation (H.R. 1735) related to Syria. For more information, see CRS Report R43727, Train and Equip Program for Syria: Authorities, Funding, and Issues for Congress, by Christopher M. Blanchard and Amy Belasco, and CRS Report R43612, The “Islamic State” Crisis and U.S. Policy, by Christopher M. Blanchard et al.