Terrorism and the Brexit vote

Our new research shows that proximity to terrorist attacks increased support for Remain

The unexpected outcome of the 2016 EU referendum caught many scholars, pollsters and practitioners by surprise and spurred a growing academic literature on this topic. Previous studies have convincingly shown that important characteristics of the population, such as education, unemployment, income and social status, as well as issues of sovereignty and immigration, have all played an important role in determining the share of votes for either the Leave or the Remain option.

Our recent study — joint with Vincenzo Bove from the University of Warwick — contributes to the literature on Brexit and public opinion formation by contending that the determinants of the referendum results should be also evaluated against the background of wider public security concerns. The United Kingdom has a long history of battling episodes of terrorism and political violence within its borders. In 2015 and 2016 only, 29 terrorist incidents were recorded in the country, excluding Northern Ireland (Global Terrorism Database). And in 2017, the year after the referendum, emblematic terrorist attacks such as those at Westminster Bridge, Manchester Arena and London Bridge killed a total of 36 people. Not surprisingly, a recent YouGov poll shows that terrorism is regarded as a top concern by the British public, more than in any other European country. As of yet, however, extant studies have neglected whether and how security concerns have shaped the outcome of the referendum.

We put forward two competing hypotheses on the impact of terrorism on support for Remain. On one hand, several studies indicate more support for reactionary nationalist, right-wing and anti-immigration parties in the aftermath of terrorist attacks. Since terrorism can affect anti-foreigner sentiments and increase concerns about less restrictive immigration policies, we expect weaker support for Remain in locations proximate to terrorist attacks. On the other hand, terrorist attacks may expose national security vulnerabilities and increase awareness of the additional security risks of leaving the EU. Terrorist attacks are found to foster both negative, particularly fear and prejudice, as well as positive emotions, such as solidarity and sense of belonging. In a context where terrorism targets other EU countries and media explicitly link terrorism to the risks of Brexit, we can expect voters to react to terrorism by holding onto the status quo. Hence, our second competing hypothesis has it that support for Remain is stronger in locations proximate to terrorist attacks.

The main identifying variation in our analysis is the distance from terrorism. Physical proximity to attacks has been found to amplify the personal sense of vulnerability and to heighten the perception of risk in terms of both the probability and the consequences of terrorism (Fischhoff et al., 2003; Braithwaite, 2013). Physical proximity to attacks can also increase counterfactual thoughts; that is, individuals thinking that “they themselves could have suffered from a disaster if the circumstances had been a bit different” (Zagefka, 2018). We employ data on 380 local authority districts, and exploit the fact that only 11% of these districts were hit by terrorist attacks since the announcement of the referendum in January 2013. Our estimation strategy is designed to address ‘self-selectivity concerns’; that is, unobserved factors affecting both the likelihood of a district to experience terrorist attacks and the voting behaviour of its residents.

We provide support for the hypothesis that terrorism increases the share of votes in favour of the EU (i.e. pro-Remain), and the result is robust to controlling for all the known socio-economic correlates of the Brexit vote. In particular, we find that, the closer is a location to an attack; the higher is the percentage of the Remain vote. In our baseline estimate, we show that two non-attacked districts that differ by 45 kilometres in terms of proximity to the attacked district are expected to differ by 1 percentage point in terms of support for Remain. As such, the effect is of considerable size and has important implications for our understanding of the EU referendum, particularly against the background of the narrowness of its outcome.

Our hypothesized effects on the Brexit vote are likely to be more pronounced for sensationalist events. We thus further investigate whether the characteristics of the attacks can mediate the effect of distance, and find that proximity to attacks has a much stronger effect on the support for Remain when they attracted prominent national media coverage, when the attacks caused casualties or when they involved Muslim or Jihadi-inspired perpetrators.

To shed light into the micro-foundations underlying the terrorism-induced Remain effects at the district-level, we use individual-level data from the British Election Study (BES) on attitudes about the EU and public mood towards terrorism salience. In particular, we exploit information on around 70 thousand individuals interviewed in the BES waves that coincided with the following three attacks: the murder of MP Jo Cox (16 June 2016); the Manchester Arena bombing (22 May 2017); the Finsbury Park attack (19 June 2017). We find that exposure to terrorism displaces attention from other key concerns, such as the state of the economy or immigration policies, and increases the perception of insecurity. At the same time, we find that, after a terrorist attack, individuals are more likely to take a more positive stance towards the EU, and to report that the risk of terrorism will be higher if the country leaves the EU.

Our analysis serves to inform the current ongoing policy debate on the factors affecting the Brexit vote, on public opinion in favour of European unification, and on the short and long-term consequences of terrorism on behavioural and attitudinal consequences. We show that the negative effects of terrorism go well beyond national elections, and can affect public support for broader political and economic issues, such as European integration. As such, the overall consequences of terrorist attacks for political behaviour and electoral outcomes are even greater than hypothesized by extant studies. Our research is a first step in this direction, and the results suggest that whether terrorism may influence other aspects of domestic politics and shape its course deserves greater scrutiny.