The EU as beacon of environmental policy? Measuring the effect of EU legislation on national policy portfolios

Across modern democracies, environmental policies are constantly accumulating. Typically, the EU is considered the central force driving environmental legislation in its member states. However, existing literature is indifferent to the actual effects of EU legislation on national policy. To answer the question of how EU legislation affects national environmental policymaking, we propose an innovative measurement concept that captures the diversity and congruence of national policy stocks in relation to EU policy. By measuring the congruence as well as the diversity of clean air policies in 12 countries from 1976 to 2018, we show that the EU’s role as a driver of environmental policy innovation is ambivalent and largely dependent on the individual country and time. Secondly, we provide a more nuanced view on countries’ innovativeness when crafting new environmental policies.