Patterns of legislative voting behaviour are structured by the different interests of the government and opposition camps in parliamentary democracies: members of parliament supporting the government mostly vote in favour of bills initiated by the cabinet, whereas MPs from the opposition normally vote against government bills. This pattern is developed less strongly in young democracies where MPs had not yet the chance to ‘learn’ how the interplay between the government and parliamentary party groups supporting the government works. We argue that the positions parties and their representatives adopt in their election manifestos and in their voting behaviour in parliament drift apart over time. We test our argument by comparing the positions of parties – estimated by a content analysis of election manifestos and by the analysis of recorded votes – in Weimar Germany in the time period between 1924 and 1932.