Political parties in most European democracies need to collaborate with other parties to come to office. Governing in coalition cabinets is characterized by programmatic compromise and the division of ministerial portfolios among coalition parties. While previous work has devoted much attention to the allocation of executive offices and uncovered a strong relationship between a party’s parliamentary seat share and the share of ministerial portfolios it receives, little is known about the allocation of policy payoffs. In an effort to close this important gap in the literature, I argue that the strength of members within a political party is crucial in explaining how close a party can pull the governmental position towards its own ideal point. Party members constrain the leadership in coalition negotiations. As policy-motivated actors, members want a coalition agreement that is close to the party position. The more party leaders are constrained by their members, the more leaders have to accommodate the members’ interests in coalition negotiations if they want to prevent future sanctioning by their members. Thus, party leaders who are confronted by strong members have an advantage in coalition negotiations as they can credibly threaten their negotiation partners not to be able to ratify the coalition agreement if it is too far from their members’ preferences.
I test my theoretical argument based on a novel dataset on coalition agreements that were negotiated by more than 200 coalition cabinets in 24 European countries from 1945 until 2015 that was generated in the Bringing Policies Back in Research Project funded by the German DFG. The content of coalition agreements was coded by human coders based on a coding scheme that is similar to the codebook of the Manifesto Project so that the success of coalition parties can be assessed by comparing their manifestos with the coalition agreements. Using this novel dataset, the theoretical argument will be tested drawing on a multilevel regression analysis. The results will have major implications for our understanding of intra-party democracy and government formation.
