Impact of Referenda on the Politicisation of issues of European Integration

This paper addresses the question of how referendum results on issues of European integration affect ongoing party competition on the referendum issue, building upon party literature regarding how parties compete as rational choice actors in order to gain advantages over their rivals (Downs 1957; Strom 1990) by taking strategic decisions in terms of position and issue salience (Budge 2015; De Vries & Hobolt 2020). Research into referenda has tended to focus on how parties have instigated public votes to gain strategic policy and electoral advantages over their rivals, or to resolve divisions on the issues within their parties or governing coalitions (Dür and Mateo 2011; Qvortrup 2018). However, research on how parties respond to the result of referendums has been limited to country-specific investigations, which have produced conflicting results as to whether referenda increase or decrease ongoing party competition on the issues (De Vries 2009; McGraw 2018). The focus of this paper is on identifying what aspects of a referendum result and individual party characteristics influence whether competition on the issues, in terms of both salience and polarisation between parties, increases or decreases in the aftermath of the public vote. The manner in which parties seek to compete over a close referendum result such may manifest either by a change in position on the issue or through altering the level of salience attached to the topic, as set out in the following hypotheses: H1. A referendum with a small margin of victory will lead to an increase in salience that parties attach to the issue, while a result with a large margin of victory will lead to a reduction in salience that parties attach to the issue. Initial results, from a nested multivariate test of 278 parties across 38 referendum cases, identify a statistically significant correlation between a decrease in the margin of victory in a referendum and an increase in salience which parties attribute to it, in line with the expectations in the hypothesis. This appears to be driven by parties that backed the losing side in the referendum perceiving an opportunity to overturn the result and gain advantages by keeping the issue high on the political agenda. H2. A referendum with a small margin of victory will increase the likelihood of parties altering their policy position on the issue in the direction of public opinion. The correlation between a rising margin of victory in a referendum and changes to party positions on the matter of European Integration is not statistically significant, so that the null hypothesis that the margin of victory in a referendum has no significant impact on party positions on the issue cannot be rejected. However, analysis of the control variables suggest this does not hold true for all parties, with parties that were internally divided on the issue or those that faced a challenge from a Eurosceptic challenger party tending to adapt their position in favour of the majority of public opinion as displayed by the referendum result.