A growing field of discursive institutionalism has argued for the importance of ideas and discourse in policy changes. The aim of the study is to analyse framing effects empirically by examining how, and to what extent, competing frames can shape public opinion on the implementation of a specific policy change. The case study focuses on the administration of social assistance in Finland. Results indicate that the framing of ideas shapes public opinion. Analyses show that some types of frames are more effective than others. To be successful, a politician must simplify the issue and appeal to moral sentiments rather than present too many difficult 'factual' viewpoints. Our study also emphasizes that even frames that succeed in shaping popular opinion may fail if powerful political actors oppose reform. Therefore, we argue that the interplay between the 'old' power resource approach and the 'new' ideational approach should be taken into account when explaining institutional changes.