How the European Union is conceptualised in the national and public political debates restricts the European policy options available to that state. It is therefore of interest to see which conceptions of the EU dominate in a country, and to understand how these can be identified and interpreted. This paper outlines a framework for discourse analysis and then applies it to the Czech public discourse on the European Union. I describe how the debate can be analysed according to three different ideal types of legitimation, based on 1) an instrumental rationalisation, 2) a “we feeling”, 3) a “good argument”. I argue that any single actor will likely use arguments drawing upon all three levels, and I conclude that the Eurosceptics (Euro-realists) associated with the Civic Democratic Party came to see EU membership as a “marriage of convenience”, a necessary evil, because their arguments went in two incompatible directions. According to the third ideal type, they had to favour membership as good for the national interest, in economic terms. Simultaneously, this conflicted with the other two levels due to their belief that the EU is a threat to national sovereignty, and their conception of the nation state as the only legitimate arena for democratic decision-making. Advocates of membership, such as Prime Minister Špidla, had a more inclusive conception of the EU, enabling the argument that the EU strengthens nation states in globalising times.