Abstract This article reviews the European Court of Justice's case-law on European citizenship in the light of aspects of the rights theories of Ronald Dworkin and Robert Alexy. More specifically, the free movement right in Article 18(1) EC is conceptualised as a Dworkinian principle and as a prima-facie right or optimisation precept in Alexy's sense. Against this backdrop the article argues that Article 18(1) can best be interpreted by drawing an analogy with the economic free movement provisions. The central argument is that the rule of reason also applies to European citizenship, or that there is a rule of reason in European citizenship. The analogy encompasses both the definition of the scope of Article 18(1) and its limitations. With regard to the latter, it is contended that there is no conceptual distinction between the limitations and conditions referred to in that provision. Particular emphasis is placed on the recent case-law concerning the question of access to welfare benefits. In this regard it is suggested that the notion of a structural link constitutes both a threshold criterion to trigger the prima-facie right in Article 18(1) as well as a benchmark for assessing the degree of solidarity owed to the migrant citizen. The rule of reason approach leads to the stipulation of a thin, juridical conception of European citizenship that does not rely in any way on thick, essentialist properties.