West Lothians in the European Parliament? Diverging Vote Choices in Cases of Differentiated Integration

Abstract Territorial differentiation entails challenges for legitimate representation as legislators may be empowered to vote on legislation that does not affect their constituencies. A typical example of this democratic dilemma is the “West Lothian question” in the United Kingdom, where all members of the House of Commons can vote on bills that only affect England. The European Union faces a similar dilemma when members of the European Parliament vote on bills from which their member states are exempted. We analyse EU legislators' voting behaviour on differentiated policies to provide the missing empirical evidence for an informed debate about the institutional design of legislative rules under differentiation. We show that legislators abstain more frequently than their party group colleagues when their constituency is not subject to a bill due to sovereignty concerns. This practice of abstention resembles an existing norm in the United Kingdom and mitigates the democratic dilemma associated with differentiation.