Ambiguous Coalitions: How parties' ideological ambiguity impact government formation

Policy-seeking theories about coalition formation state that ideological coherence among the parties plays a pivotal role in explaining the formation of governments. However, these theories often assume that parties hold perfect information about the policy preferences of the other actors. While this assumption can be helpful, it also oversimplifies the conditions under which actors behave. This study addresses this issue by incorporating the role of ideological ambiguity and consequentially relaxing the perfect information assumption. I test two hypotheses: first, ideological ambiguity reduces the likelihood of forming a government; second, ideological ambiguity is more relevant when parties hold similar preferences. Relying on data from 14 European countries (1997–2019), I find support for both hypotheses. This study contributes to the literature on coalition formation by introducing a measure of ambiguity at the level of coalitions, investigating the potential effects of ideological ambiguity, and offering insights for future research.