The transformation of the European Parliament's voting dimensions: agenda-driven or secular change?

We investigate whether pro-/anti-European integration stances have become the most relevant dimension of voting in the European Parliament (EP), superseding the traditional left-right axis. Using a new database with more than 41 million observations on roll-call votes cast in the EP during 1979-2022, we show that the pro-/anti-European axis became the main dimension of voting during the eurozone crisis. We challenge the view that this was the result of a temporary change in the legislative agenda dictated by the crisis and affecting only a few policy areas. We find that the European dimension grew across all policy areas, suggesting that the EP has undergone a secular change in which pro-/anti-European stances have become the main dimension of voting regardless of any agenda changes. Our findings indicate that the emergence of eurosceptic far-right parties in the EP was a key driver of this change.