This paper on international law and European nationality laws is based on the findings from country reports produced within the framework of the EUDO Citizenship Observatory as well as further correspondence with country experts who participated in this project. After a brief description of the history and sources of public international law on nationality, the domestic impact of international legal provisions in this field is being examined. To this end, the second part of this paper discusses the key factors which determine state receptivity towards international law on nationality. These include historical, regional and political factors, internal doctrinal preconditions, informal factors such as societal pressure as well as systems of reservations and the absence of independent review in international Treaty law. The regional influence of the European Convention on Nationality (ECN), as the most important multilateral instrument at present, is analysed in more detail in the last part of the paper including a description of common obstacles to ratification of the Convention.Research for the EUDO Citizenship Observatory Comparative Analyses has been jointly supported by the European Commission grant agreement JLS/2007/IP/CA/009 EUCITAC and by the British Academy Research Project CITMODES (both projects co-directed by the European University Institute and the University of Edinburgh)
