This article describes the evolution of political conditions for accession to the European Community from 1957 to 1973 on the basis of the responses of the Community and national parliaments to applications for association (Article 238 EC Treaty) and membership (Article 237 EC Treaty) and to a US foreign policy initiative. It challenges the thesis that the European Community was originally uninterested in the political nature of its members as long as they were non‐communist and that the Community made a volte face in 1962 in reaction to a request for an association agreement by Franco's Spain. It argues that the Copenhagen political criteria, except minority protection, were firmly established by 1973 after a series of pronouncements and decisions by the European Parliament, national parliaments (both 1962), the Commission (1967) and the Council (1973). The article aims to contribute to the early history of the constitutionalization of the Union and discusses how demands from outsiders prompted the Six to define the constitutional requirements for (candidate) members. It is partly based on new archival research.