'Second-order' versus 'Issue-voting' effects in EU referendums - Evidence from the Irish Nice Treaty Referendums

Are referendums on EU treaties decided by voters' attitudes to Europe (the 'issue-voting' explanation) or by voters' attitudes to their national political parties and incumbent national government (the 'second-order election model' explanation)? In one scenario, these referendums will approximate to deliberative processes that will be decided by people's views of the merits of European integration. In the other scenario, they will be plebiscites on the performance of national governments. We test the two competing explanations of the determinants of voting in EU referendums using evidence from the two Irish referendums on the Nice Treaty. We find that the issue-voting model outperforms the second-order model in both referendums. However, we also find that issue-voting was particularly important in the more salient and more intense second referendum. Most strikingly, attitudes to EU enlargement were much stronger predictors of vote at Nice 2 than at Nice 1. This finding about the rise in importance of attitudes to the EU points to the importance of campaigning in EU referendums.