Recently there have been calls for a politicisation of European Union (EU) decision-making. This study discusses how politicisation can be achieved and how it affects the way national parliaments fulfil their citizen- and government-related functions in EU decision-making. First, it is argued that politicisation requires legislative Commission proposals that polarise between centre-left and centre-right actors. By changing the incentive structure of national parties, such proposals help to overcome parties' reluctance to discuss European issues publicly and hence provide citizens with electoral alternatives in EU decision-making. Second, it is argued that the higher salience of polarising proposals also increases national parliaments' attention for, and hence control over, the processes on the European level. The plausibility of the arguments is evaluated empirically through a comparative case study of the discussions in Germany and Austria on probably one of the most politicised examples of day-to-day EU decision-making in recent years - the Services directive.