Negative campaign statements, coalition heterogeneity, and the support for government parties

European party systems have become increasingly complex in recent years, resulting in ideologically more heterogeneous coalition governments with far-reaching policy compromises. Consequently, an important goal of the parties' electoral campaign strategies is to present the voters a distinct policy profile on which the electorate can evaluate the competing parties. We argue that voters reward those coalition parties that attack their government partners in the election campaign and try to clarify their programmatic positions with the help of a more aggressive campaign strategy. Based on data from the CSES, the Comparative Manifesto Project database and a novel data base on party campaign statements in seven European countries from 2007 to 2018, we find that voters’ support for coalition parties increases if the latter attack their partners in the last four weeks before election day. Yet, this relationship is only observable in contexts when the ideological diversity of the incumbent coalition government is rather low.