This article takes the fiftieth anniversary of the Treaty of Rome as an opportunity to reflect upon half a century of academic discourse about the EU and its antecedents. In particular, it illuminates the theoretical analysis of European integration that has developed within political science and international studies broadly defined. It asks whether it is appropriate to map, as might be tempting, the intellectual ‘progress’ of the field of study against the empirical evolution of its object (European integration/the EU). The argument to be presented here is that while we can, to some extent, comprehend the evolution of academic thinking about the EU as a reflex to critical shifts in the ‘real world’ of European integration (‘externalist’ drivers), it is also necessary to understand ‘internalist’ drivers of theoretical discourse on European integration/the EU. The article contemplates two such ‘internalist’ components that have shaped and continue to shape the course of EU studies: scholarly contingency (the fact that scholarship does not proceed with free agency, but is bound by various conditions) and disciplinary politics (the idea that the course of academic work is governed by power games and that there are likely significant disagreements about best practice and progress in a field). In terms of EU studies, the thrust of disciplinary politics tends towards an opposition between ‘mainstreaming’ and ‘pluralist versions’ of the political science of EU studies. The final section explores how, in the face of emerging monistic claims about propriety in the field, an effective pluralist political science of the EU might be enhanced.