Muddying the Waters: Use of Vagueness in EU lawmaking

European Union (EU) legislation varies considerably in how precisely its measures are defined, with important implications for policy implementation and effectiveness. Yet, we know surprisingly little about the factors that lead EU policymakers to propose and adopt legislation with more precise or more vague formulations. This study identifies two main drivers of the strategic use of policy vagueness in the EU policymaking process. First, intra- and inter-institutional disagreements incentivize legislators to obscure policy details to facilitate compromise and increase the likelihood of adoption. Second, high levels of politicization — and the associated potential for public scrutiny — prompt EU legislators to favor less stringent and more flexible formulations. This strategy allows them to accommodate diverse levels of public support for EU policy and mitigate risks of electoral backlash. We test these expectations using data on legislative proposals introduced and adopted between 2009 and 2024. Our findings contribute to research on the precision of legal texts and EU legislative politics and inform broader debates on political responsiveness in multilevel governance systems.