Literature produced concerning social mobilization oftentimes wavers between two tensions: either it is too agency-laden, missing the necessary account of historical and social contexts, or it is too deterministic, missing an understanding of the generative capacities of mass movements in the constitution of new political subjects and frames. While both methodologies offer useful conceptual tools for understanding the development and productive potential of social mobilization, the peculiar case of the Kassioun Current in Syria reveals the extant shortcomings in the agency-laden/deterministic dichotomy and, thusly, indicates the possible mistreatment of other curious cases, too. The Kassioun Current, which split from the Syrian Communist Party (Bakdash) in 2000, offers us an interesting entry-point into the exceptions of political organizing under authoritarian rule in Syria. While Kassioun was unlicensed and, thus, de facto illegal, it was still extended the space to pursue political work at a time when Damascus Spring organizations were brutally repressed (2000-2005). With the emergence of the 2011 Uprising, Kassioun experienced a transformation in its political program and, with it, the rise of internal contradictions. While the organization was legally registered and incorporated into the regime’s structure in 2012, many of its members who disagreed with the organization’s political line in regards to the 2011 popular movement left its ranks. Under the organic leadership of older Marxists like Sal?mah Kaylah, the radical youth of Kassioun established a mass organization called Revolutionary Syrian Youth and faced death or detainment as they organized protests, provided relief to affected areas and internally displaced civilians, and produced a newspaper called Yasari (Leftist). My paper will aim to (1) situate the Kassioun Current within the historical field of political organization in Syria, (2) reveal the antagonisms among the Syrian Left within the socio-historical context of Syria prior to and following 2011, and (3) understand the conditions of possibility for new forms of broad leftist political organization under a “crisis of authority” i.e. the crisis of the state during the 2011 Syrian Uprising.