Radical Weakness—Do Radical Parties Receive Fewer Ministries?

Radical parties’ electoral surge has intensified debates about their inclusion in government coalitions. This article presents the most extensive analysis of ministry allocation to date, covering data from 555 coalitions from 33 OECD countries since World War II. While Gamson’s Law suggests coalition participants receive ministries proportional to their parliamentary seats, both coalition formation theory and ministry allocation theory imply that radicalism weakens bargaining power. Additionally, empirical research links radical parties to prioritisation of policy payoffs. I propose a theoretical model distinguishing between types of radicalism, identifying distinct mechanisms leading to ministry undercompensation. My findings show that radical parties systematically receive fewer ministries, primarily due to reduced bargaining power rather than because of payoff preferences. Moreover, I demonstrate that the factors facilitating coalition entry are closely linked to those shaping ministry allocation. Using selection bias-robust modeling, this study offers new insights into the constraints radical parties face in government formation.