Frontiers of Equality in the development of EU and US citizenship

If we wish to understand the development of the citizenship of the European Union and its relationship to the nationalities of the member states, it is helpful to examine the history of United States citizenship and, in particular, to elaborate a theory of "duplex" citizenships found in federal orders. In such a citizenship, each person’s citizenship is necessarily "layered" with the citizenship or nationality of a (member) state, a legal status which can resemble subjecthood to a monarch in its exclusive claim to the holder’s allegiance. The research question of this doctoral dissertation in European constitutional law is: how can a duplex citizenship be seen and be understood to affect the exclusiveness of a singular citizenship, nationality or subjecthood? The thesis is that it can be understood by considering different aspects of and claims to equality inherent in citizenship, which affect the exclusivity of the claim of allegiance as found in subjecthood. Even if the substance of this study is mostly (constitutional) law, its method is historical (largely following a chronological line of development, in fact) and comparative. It is not doctrinal, nor normative.