Referendums in the European Union
Referendums are frequently used by the European Union (EU) to ratify EU-related propositions. There are three main types of referendums: (a) on joining (or leaving) the EU, (b) ratification of new EU treaties or agreements, and (c) advisory referendums on particular EU-related issues, like whether Turkey should join the EU. While referendums have been widely criticized as being decided by ”second-order” factors such as governmental popularity, there is evidence that, when a proposition matters for voters, voting behavior is dominated by issue-voting. However, even when issue-voting dominates in high salience referendums, there is also evidence that voters hold a status-quo bias; and in instances where a vote is close, voter dispositions to keep what they know instead of opting for more unsure gains can tip the balance towards a no vote. In lower salience referendums, party cues and recommendations play a significant role.
When referendums are close, campaign effects and the importance of information provided by campaigns matter. Information and debates can make an issue salient for voters and can provide sufficient information to enable the voters to match voting intention with their underlying EU attitudes. However, not all voters react to campaign information in the same fashion. For example, pro-EU information can make voters with negative EU atittudes even more prone to vote no, whereas voters with positive EU attitudes are not as strongly motivated.
In the past several years, most EU referendums have resulted in negative outcomes. There have been negative outcomes in low salience referendums in countries like the Netherlands, where there is evidence that second-order factors mattered. In contrast, in the December 2015 referendum in Denmark on transforming the Danish opt-out into an opt-in on Justice and Home Affairs, Danes decided based on their EU attitudes (issue-voting). In particular, opponents of more integration were more highly motivated, pushing the outcomes towards a clear no. In June 2016, a majority of British voters decided to leave the EU based on their negative attitudes towards the EU, in particular because of economic and identity-based fears about the downside of EU membership relating to immigration and sovereignty.