Drivers of parliamentary opposition in European Union politics: institutional factors or party characteristics?

A vital political opposition is one of the cornerstones of democracy, yet we know surprisingly little about the conditions that shape it. In this paper, we offer a comprehensive assessment of the drivers of parliamentary opposition in European Union (EU) politics in five countries: Denmark; Germany; Ireland; Sweden; and the United Kingdom. Based on an extensive hand-coded data set of 7,520 statements made by members of parliament (MPs) during both plenary sessions and deliberations during European Affairs Committee (EAC) meetings, we examine how institutions and party characteristics shape two types of oppositional behaviour: the expression of critique and the presentation of alternatives. We find that both factors are important for understanding to what extent, and how, opposition is voiced in national parliaments. Oversight institutions’ strength and a party’s degree of Euroscepticism jointly function as significant determinants of the likelihood that MPs will express opposition in the form of critique. However, when it comes to the likelihood of offering alternatives, oversight institutions’ strength fails to explain variations in the share of alternatives, while degree of Euroscepticism remains a significant predictor.