A remarkable reform in modern Swedish political history was the transformation of the local government structure between 1952 and 1974. In a mere 22 years, the number of municipalities was reduced from 2,498 to 277. This study aims to answer how such large-scale reforms could come about politically, particularly since much of the literature on institutions and political reform asserts that carrying out large-scale political change should be a difficult task. Two opposing stories of institutional change are presented: evolutionary accounts, which see the amalgamations as rational adaptations to changing circumstances, are contrasted with a social conflict perspective, which explains amalgamations in terms of their distributional consequences. By investigating the processes leading up to this vast restructuring of Swedish local political geography, we demonstrate that an understanding of these reforms as rational adaptations to changing circumstances, made on the basis of consensus among leading political actors, is not accurate. The reforms were not as uncontroversial and non-conflictual as they often have been portrayed. Our results weaken the evolutionary approach to institutional change, whilst supporting the social conflict perspective.