The European Union (EU) is imbued by the legacy of the empire. Practically all of its Member States have been either former colonial powers or former colonial subjects. The eastern part of the EU has a specific baggage and legacy that it brings to the EU. After 1989 the smaller and bigger countries of Central and Eastern Europe (CEE) have undergone major transformations from being homo Sovieticus to becoming a fully-fledged member of the European family and ‘the West’. All countries have chosen their own specific paths in this journey, some recently more problematic than others. Estonia is an example of arguably one of the most Europhile paths of them all. This because of a need and want to be a ‘good European’ and it can be traced in both national grand narratives and more practical court practice. What has caused these understandings of Estonia in the EU and the EU in Estonia is the main question of this paper. It tries to unpack the precarious relationship between sovereignty, security and EU law primacy claims as the main constitutional conundrums of the Estonian EU membership and European constitutional imaginaries. What feeds into some ontological insecurities and idiosyncratic understandings of sovereignty in the country? It proposes that the country’s postcolonial predicament might be a way to explain these puzzles.