Radical Parties Get Fewer Ministries — Reduced Bargaining Power Explains Why

📊 A Postwar Look at 555 Coalitions

This study examines whether radical parties receive fewer ministries when they join government. The analysis draws on the largest existing dataset of cabinet formation: 555 coalition governments across 33 OECD countries from World War II to the present.

🧭 A Model That Distinguishes Types of Radicalism

Theoretical background integrates three strands:

• Gamson’s Law, which predicts ministries are allocated roughly in proportion to parliamentary seats.
• Coalition formation and ministry-allocation theories, which suggest that radicalism can weaken a party’s bargaining power.
• Empirical literature linking radical parties to a stronger emphasis on policy payoffs rather than office-seeking.

The article proposes a formal model that separates different forms of radicalism and identifies distinct mechanisms by which radical parties might be undercompensated in ministry shares.

🔎 What the Evidence Shows

• Radical parties systematically receive fewer ministries than their seat share would predict.
• The primary mechanism behind this undercompensation is reduced bargaining power, not a preference for policy payoffs.
• Factors that make it easier for radical parties to enter coalitions are closely related to the determinants of how ministries are allocated once they are in government.

🛠️ How This Was Tested

• Large-N comparative analysis covering 555 postwar coalitions in 33 OECD countries.
• Models account for potential selection bias into coalitions using selection-bias-robust estimation techniques to separate entry effects from allocation outcomes.
• Results hold across specifications that explicitly consider both office-seeking and policy-seeking motives.

💡 Why It Matters

Findings refine expectations about power-sharing in multiparty democracies: even when radical parties join coalitions, they often hold fewer ministries than proportional norms predict. This reflects structural bargaining disadvantages more than strategic trade-offs over policy, and highlights a link between coalition inclusion and subsequent ministerial influence. The study provides new empirical and theoretical insight into the constraints radical parties face in government formation.