Parties are always right: the effects of party cues and policy information on attitudes towards EU issues

This article analyses the influence that political parties exert upon citizens’ opinions about European Union issues. By measuring at the same time the content and source effects on political attitudes, the article considers the possibility that voters pay less attention to the arguments used in a political message than to its source. Results from an online survey experiment in Spain show that partisan voters use a heuristic model of processing when taking positions on an unfamiliar EU issue, even though the prevalence of the source effect is moderated by the respondent’s political sophistication and party attachment. The results also indicate that some respondents tend to pay less attention to a message’s content when the message comes from their preferred party. Such findings raise concerns about the possibility for EU issue voting to guarantee the accountability of political elites and party–voter linkages.