Opting out from European Union legislation: the differentiation of secondary law

Differentiated integration in the European Union (EU) has been primarily discussed and analysed at the treaty level, whereas lack of systematic data has hampered the examination of secondary-law or legislative differentiation. We present a new data set of differentiation in EU legislation from 1958 to 2012, a descriptive analysis and a comparison of the patterns of primary- and secondary-law differentiation across time, member states and policies. We find that differentiation facilitating the accession of new members and constitutional differentiation accommodating the opposition against the integration of core state powers drive both primary- and secondary-law differentiation. In addition, we find complementarity between differentiation in treaty law and secondary legislation depending on the availability and salience of differentiation opportunities.

欧洲联盟（European Union，EU）的差异化整合研究多集中于条约层面的探讨与分析，而系统性数据的缺失阻碍了针对次级立法或立法层面差异化的考察。本研究构建了1958年至2012年欧盟立法差异化的全新数据集，并针对不同时间维度、成员国与政策领域内的基础法与次级立法差异化模式展开描述性分析与对比研究。研究发现，助力新成员国加入的差异化机制，以及为应对核心国家权力整合的反对声音而设置的宪法层面差异化，共同推动了基础法与次级立法的差异化进程。此外，研究还发现，条约法与次级立法中的差异化措施存在互补性，且该互补性取决于差异化机遇的可获得性与显著性程度。