This paper deals with case-based reasoning and proportionality analysis in the CJEU case-law. The case, constructed by the Court, functions as a framework in which proportionality analysis takes place. The justification of national measures restricting free movement is a subversive process for national governments : it implies an entirely different way of speaking and thinking. This becomes clear when one considers the role of the case in the reasoning of the Court. The objectives of national measures must be reconstructed within a specific intellectual framework and in the context of a specific case. In this process of conceptual translation, accomodating the diversity of cases in the application of a rule is often a proportionality requirement. Nevertheless, and quite paradoxically, it could also make the proportionality of a rule more difficult to establish.