"The summer 2014 offensive in neighboring Iraq by the insurgent terrorist group known as the Islamic State (IS, aka the Islamic State of Iraq and the Levant or ISIL/ISIS) has reshaped longstanding debates over U.S. policy toward the three-year old conflict in Syria. The Islamic State controls large areas of northeastern Syria, where it continues to clash with forces opposed to and aligned with the government of Bashar al Asad. Meanwhile, fighting continues in other parts of Syria, pitting government forces and their foreign allies against a range of anti-government insurgents, many of whom also are engaged in battles with IS forces. Since March 2011, the conflict has driven more than 3 million Syrians into neighboring countries as refugees (out of a total population of more than 22 million). Millions more Syrians are internally displaced and in need of humanitarian assistance, of which the United States remains the largest bilateral provider, with more than $2.4 billion in funding identified to date. [...] Congress is considering FY2015 appropriations legislation (H.R. 5013/S. 2499) that would reauthorize the provision of nonlethal assistance in Syria for certain purposes notwithstanding other provisions of law and prohibit the use of defense funds to provide man-portable air defense weapons (MANPADs) to entities in Syria (H.R. 4870). Senate committees have endorsed FY2015 defense appropriations and authorization legislation (H.R. 4870/S. 2410) that would support arming and training of vetted opposition forces for select purposes. Congress also may consider measures to authorize or restrict the use of force against the Islamic State in Syria and beyond."
CRS Report for Congress, RL33487