This chapter starts from the premise that political actors, and professional politicians in particular, have a clear conception of what they are doing and what the rules are under which they are playing. Taken together these conceptions should add up to something like a practical theory of democracy. Moreover, these theories can be expected to be shared by actors in the same polity during the same time (although competing theories are entirely possible). Therefore, I propose to take a closer look at the theories of democracy politicians hold and to compare prevailing practical theories internationally and over time. In this chapter I focus on a historical study of three German politicians in the Weimar Republic. As categories of analysis, I emphasize the institutional and relational aspects of democracy, that is, the understanding of the institutional order and of relations to other actors (to citizens, members of the same party, political opponents, other institutions, the media, interest groups etc.). As the focus is on the shared understanding, I include representatives of ideologically very different political parties. Methodologically, the chapter makes use of the autobiographies of members of the Reichstag. The analysis is based on a relatively new qualitative technique called Collective Mindset Analysis (Deutungsmusteranalyse).