From Proposal to Adoption: How EU Legislators reshape Executive Delegation Design

EU policies vary in implementation design, with some granting discretion to member states' national administrations and others to the European Commission. While extensive literature examines delegation in multilevel governance structures, it focuses exclusively on final delegation designs, overlooking how EU actors arrive at these decisions. Filling this gap, the paper examines why and how the European Parliament and the Council of the EU alter the Commission's proposed delegation designs. Drawing on policy responsiveness literature, we expect proposals expanding EU authority relative to national authority to undergo more substantive changes during legislation, particularly limiting Commission involvement and increasing reliance on national administrations in highly politicized policy areas. We test these expectations using a novel dataset of EU policies proposed and adopted between 2009-2024, Eurobarometer survey measures of public attitudes towards EU integration, and text analysis with machine learning to measure agency discretion and EU authority expansion. The research reveals how legislative contestation shapes executive delegation patterns with substantive implications for EU authority and member state sovereignty.