The philosophical and political advantages tied to a break with Marxist thinking have been notable. With such a break with Marxism, economic and scientific determinism have been discounted—and it is in this sort of determinism that a classic critique of Marxism finds a reason for discrediting the Marxist-Leninist project. However, it seems that the cost of totally abandoning Marxist thinking has not been sufficiently examined. This article proposes a comparative study of two philosophers’ conceptions of conflict: Chantal Mouffe’s perspective will be examined and compared to Cornelius Castoriadis’s view of radical democracy and its treatment of conflict. The article seeks to show that a full break with Karl Marx weakens political radicalism. In other words, by opting for a perspective on conflict that fully renounces the Marxist view, Mouffe is doing away with the idea of direct democracy and/or that of a revolutionary project. Her approach differs from that of Castoriadis who seeks, in some sense, to remain faithful to the emancipatory aspects of Marxian thought.