This book examines the history of the Palestinian Left by focusing on the trajectory of the Popular Front for the Liberation of Palestine (PFLP) during its declining phase. Relying on a substantial corpus of primary sources, this study illustrates how the PFLP's political agency contributed to its own marginalisation within the Palestinian national movement. Following the 1982 eviction of the Palestine Liberation Organisation (PLO) from Lebanon, the bases of the PFLP's opposition to Fatah's primacy in the national movement were jeopardised. This book argues that the PFLP's loyalty to the PLO institutional and political framework prevented the formulation of a real counterhegemonic political project. This drove the PFLP's action to suffer a fundamental contradiction undermining its stance within the national movement. In the attempt to continue its opposition to Fatah, while maintaining integration in the Palestinian mainstream, the PFLP's agency fluctuated, compromising its effectiveness and credibility. Apparently irreversible, the PFLP's marginalisation is a factor fostering the current Palestinian impasse, as no alternative is emerging to break the thirteen-year long Hamas-Fatah polarisation.