Sleeping with the enemy Is there a Spatial Diffusion of Unorthodox Coalitions in Swedish Local Government?

A remarkable development has taken place in the Swedish local government coalition landscape. From historically being borderline inconceivable, the Social Democrats and the Moderate Party nowadays partake in ruling coalitions in almost 1/5 of the municipalities. Not only is this somewhat of an historical anomaly, it is disrupts expectations from established theories of coalition formation. This paper sets out to enhance our understanding of why this curious development has come about. We tentatively explore the validity of an ‘diffusion of innovation’-based argument stating that breaking normative barriers for cooperating with an historical political arch-enemy will be observed in geographical clusters. These parties will dare to take the risk of cooperating with one’s historical nemesis if similar decisions are made by one’s local sister party branches in adjacent municipalities. Ultimately, although the mechanisms underlying the association are somewhat unclear, we do indeed observe that coalitions including the Social Democrats and the Moderates have a tendency to cluster geographically in neighbouring municipalities.