Over the last seventy years Europe has seen government authority decentralised to subnational bodies, offering up new arenas for political contestation. At the same time, the typical cleavages in society that provided solid bases of support for political parties have crumbled, leaving parties in search of new alliances to obtain governing power. Political parties find themselves caught between the desire to get into office in as many government authorities as possible and the desire to present a coherent brand to the public, as signalled by their coalition partner choices. This research project stands at this tense intersection of interests and provides new clarity to the historical record and some exploratory lines of inquiry into the effects of this dynamic. The existing work on measuring the extent to which regional and national governments mirror each other is investigated and critiqued in order to develop a new operationalisation of coalition congruence that is amenable to large-N research. On the basis of this new measure, the historical record from 1945 to 2015 of coalition congruence in nine Western European countries (Austria, Belgium, Denmark, Germany, the Netherlands, Norway, Spain, Sweden, and Switzerland) is mapped out in order to identify broad trends running alongside the wider trend of dealignment from party politics. Following this, a number of hypotheses about the institutional determinants of congruence and effects of congruence on party perceptions are explored. The number of regional governments that cut across the government-opposition divide has been on the increase in Europe, especially so in some countries, and these cross-cutting governments appear to play a role in party attachment, but not through the causal mechanism of shifting left-right perceptions of party brands as expected by the literature. This project adds a new operationalisation of a concept, a new empirical dataset, extends the branding model of partisanship to the subnational level, and contributes to moving forward the fourth wave of coalition studies.