Replication Data for Political Preferences, Policy Loss and Shifting Support for European Integration

What explains the relationship between political preferences and support for European integration? Why did people on the Left oppose, and Right support, European integration in the 1980s, but this pattern reverse in the 2020s? We argue that citizens evaluate European integration in a transactional way in terms of their assessment of EU policy outputs. If the European Union offers citizens policies in line with their political preferences, they support it. If not, they oppose it. We find support for this argument using individual level public opinion data (n>1,100,000) from all EU member states over almost 50 years (from the mid 1970s to the present) and novel approaches for measuring the left-right policy location of EU legislative outputs.