Electoral cycle timing and popular support for a treaty are crucial in determining whether parties advocate referendums on European integration

David Cameron is committed to holding a referendum on the UK’s EU membership should he win a majority at the next general election. In an effort to understand why parties call for referendums on European integration, Andreas Dür and Nikitas Konstantinidis look at data from the ratification of the EU’s Constitutional Treaty in 2004. They find that the amount of time until the next election has a significant impact on whether parties choose to support referendums or not, and that parties are far more likely to advocate a referendum on unpopular and controversial issues.