Replication Data for: Coalition-Building and Consensus in the Council of the European Union

Although qualified-majority voting is possible, member states in the Council of the European Union (EU) still adopt most policies by consensus. The agent-based model of coalition building in multilateral negotiations presented here addresses this puzzle. The model demonstrates that consensual decisions may emerge as an unintended by-product of government representatives’ desire to form blocking coalitions. A qualitative case study demonstrates the plausibility of the model's assumptions and resulting coalition-building dynamics. Moreover, a quantitative test shows that the model's predictions correspond closely to the observed consensus rates. Finally, computational experiments predict a positive effect of the voting threshold but no effect of increases in membership on winning coalition size, which has important practical implications for institutional design and enlargement policy.尽管可采用特定多数投票制（qualified-majority voting），欧洲联盟（EU）理事会的成员国仍以协商一致方式通过绝大多数政策。本文提出的多边谈判联盟构建基于智能体的模型（agent-based model），解答了这一学术谜题。该模型表明，协商一致决策可能作为各国政府代表组建阻挠性联盟（blocking coalitions）这一诉求的非预期副产品而出现。一项质性案例研究验证了该模型假设及由此产生的联盟构建动态机制的合理性。此外，量化检验结果显示，该模型的预测结果与观测到的协商一致通过率高度吻合。最后，计算实验表明，投票门槛对获胜联盟规模存在正向影响，而成员国数量增加则对获胜联盟规模无显著影响，这一结论对制度设计与扩员政策具有重要的实践指导意义。