As calls emerge for cooperation with the Assad regime to help roll back the advances of the Islamic State (ISIS) in Iraq and Syria, Felix Legrand argues that the Free Syrian Army (FSA) is the only actor in the conflict with the capacity and local legitimacy to defeat ISIS in Syria. This paper analyses the FSA fighting groups that could constitute both the central elements of the fight against ISIS and the core of a reunified army for Syria’s eventual political transition.

Breaking down the new dynamics within the Syrian rebellion, Legrand sees a re-emergence of moderate FSA brigades as key players in the conflict. Islamist-funded groups, once dominant within the armed opposition, are facing unprecedented difficulties and internal divisions. FSA brigades displayed their strength in winning significant military victories against ISIS in Aleppo and Idlib in 2014. They have built upon this strength through promising alliances with Kurdish militias and the increased use of advanced anti-tank weapons. Despite their successful use of American TOW missiles, proving that well-vetted rebel groups are capable of using sophisticated weapons effectively, Syrian rebels require further assistance to effectively protect territory under their control from regime airstrikes.