This paper investigates the formation of coalition governments at the sub-national level in Swit-zerland. Quite unique, cantonal governments are elected under a multi-member majoritarian vote system. Since the 1970s, these elections have become increasingly congruent with Swiss national elections, and therefore more competitive. All theory would predict that contested elections un-der majoritarian rules lead to single-party dominance of small coalitions; the Swiss cantons are a clear exception to this rule. While earlier studies point to elite compromises, our model shows that voters and the political space's dimensionality can drive the formation of large cantonal gov-ernments. More precisely, the reconfiguration of the national political space has affected the can-tonal political landscapes, and most cantons are no longer dominated by a compact political ma-jority. The empirical study is based on a novel dataset, measuring the positions of cantonal parties and electoral results for all 26 cantons over the period of 1973-2013.
