This article takes a look from a socio-legal perspective at the historically determined outlines of the ratio juris of today’s lex mercatoria and of the ratio status of today’s Communitas Mercatorum, in relation to the salient characteristics of contemporary legal and political dynamics, paying particular attention to the European project and constitutional process. After a brief description of the historical evolution of these variables, whose purpose is to correct the simplifications instigated by the tradition of positive law, the analysis then concentrates on the current socio-legislative context, whose distinctive trait is not in fact the so-called globalisation of law, but, on the contrary, the co-evolutionary, asynchronous, asymmetric and non-systemic coexistence of a multiplicity of phenomena of pluralism, among which pride of place goes to institutional incompatibility, legal fundamentalism and interlegality. On the basis of these precepts, the article then goes on to highlight the salient political question of today’s legal experience, i.e. the war being conducted by the big supranational and transnational economic corporations against the provisions of legal orders legitimated politically by the modern sovereign state, in order to gain the upper normative hand over social dynamics as a whole: a war that features the instrumental use of the lex mercatoria both on the technical and on the ideological plane. In view of the current trend in this war, what emerges is the importance of today’s efforts to achieve political and legal construction at the European level, whose purpose is to protect the symbolic and material borders of the European political economy by erecting a system of fundamental rights and freedoms, with respect to which the lex mercatoria itself certainly functions as an integral part of the Jus Commune Europae.