On June 20, 2016, citizens of the United Kingdom voted in a referendum asking whether the UK should remain a member of the European Union or leave, causing “Brexit.” The slim victory for Brexit came as a surprise, if not a shock, to many observers. Resolving what exactly the vote meant and how best to respond to it has dominated UK politics ever since.

This book is an ambitious and impressive attempt to explain the Brexit vote. What sets the book apart from other accounts is that it engages the topic comprehensively and brings original survey evidence to bear on a broad set of important questions about which we have largely only speculated. Harold D. Clarke, Matthew Goodwin, and Paul Whitely use this evidence to address both popular accounts of the Brexit campaign and vote and the academic literature on related general topics—for example, referendum voting behavior. Their findings suggest that many popular conceptions of the referendum need revision. Moreover, the forces they identify as being at work in the referendum may prove important for understanding domestic and international politics in Europe for some time to come.

The book is organized chronologically, but with valuable asides to add context. The authors set the stage with a review of the political context surrounding then–Prime Minister David Cameron’s execution of his campaign promise to renegotiate the UK’s membership and then put it to a popular vote. This includes a detailed description of the campaign and the strategies employed by the “Remain” and “Leave” sides. The authors then step back from the unfolding drama to engage two important topics. First, they analyze trends in UK public support for EU membership and advance a “valence” argument for why support has varied—sometimes quite dramatically—since the mid-2000s. Second, they examine the rise of the United Kingdom Independence Party (UKIP). This is based on an original survey of UKIP members and a study of electoral support for the party. These two pieces of the puzzle are then used to explain the referendum vote itself. The explanation features original survey data collected directly before and after the referendum. Brexit concludes with a discussion of the likely consequences of the vote for the UK and for European politics more generally.

The evidence from the authors’ analyses supports several revisions to the conventional account of the vote. Perhaps the most striking finding is that, for many voters, the referendum was largely about domestic political considerations, not EU membership. Clarke, Goodwin, and Whitely show that even late in the campaign, large shares of the UK public did not consider leaving the EU consequential for foreign affairs, immigration, their personal finances, or the economy overall. More generally, the UK public had not considered the EU a pressing or significant political issue for several years prior to the referendum (Ipsos Mori Issues Index, July 2018). It is not surprising then that voters’ evaluations of leaving the EU were driven primarily by valence considerations: for example, their views of party leaders, their partisanship, their national identity, and the performance of the government in addressing the dominant issues of the day. Consequently, we should not have been surprised that the electorate failed to follow the broad elite consensus opposing Brexit based on the merits of membership.

According to the authors’ valence politics argument, the domestic political context was key to the vote, and that context likely tipped the balance in favor of Brexit. First, the traditional parties were nominally supportive of Remain, but their popularity and internal divisions limited their influence on voters. The Conservative government was not highly popular or seen as effective at managing the key political problems of the day—the National Health Service (NHS) and immigration. Moreover, the traditional home for protest votes—the pro-Remain Liberal Democrats—had lost that role by serving in coalition with the Conservatives. That left only pro-Brexit leaders to captivate the disaffected voters. Boris Johnson was, at the time, the most favorably viewed politician in the public debate. And, UKIP provided the main protest party. Johnson and UKIP aggressively campaigned for Leave. Finally, the Leave campaign was much more effective at engaging the top issues to voters, connecting departure from the EU with improved financing for the NHS and greater control over immigration. The authors show that these factors mattered for vote choice and probably swung it. It is interesting to note that this explanation also underscores that the timing of the vote was important. Held under different conditions, such as with Johnson’s current low popularity level, the vote could have gone the other way.

Second, the book presents fascinating evidence about UKIP and its electoral base. The chapters on UKIP feature data from an original survey of its members. This provides interesting comparisons of UKIP supporters with the general UK electorate. For instance, we learn that the highly negative views of UKIP voters regarding immigration, ethnic minorities, and the banking industry are very similar to those of the UK public. UKIP voters stand out in their frustration with the political system and the saliency of immigration and EU membership as political problems.

The authors conclude by assessing campaign claims about the consequences of the vote for economic growth in the UK, the level of immigration, and the quality of UK governance. The strength of this chapter is that it answers these questions with original empirical evidence based on the EU’s and the UK’s postwar experience. This is clearly superior to much of the casual argumentation during the campaign and in current public discourse. Their evidence suggests little, if any, costs from Brexit on these fronts. However, the analyses fall short of the high standards set in the earlier chapters. For example, Clarke, Goodwin, and Whitely conclude that EU membership has had no effect on the UK’s economic growth, based on a statistical analysis of the UK’s postwar economic performance. The key finding is that EU membership had no direct effect on growth after controlling for a standard set of domestic economic factors. But they fail to review or engage relevant literature (e.g., Barry Eichengreen and Andrea Boltho, “The Economic Impact of European Integration.” Cambridge Economic History of Modern Europe, 2010) in designing the analysis. This is important, since all arguments of which I am aware expect the economic integration associated with EU membership to stimulate growth through the domestic economic factors that are included in the statistical model. That is, the effect of membership on growth should be indirect, which is consistent with their findings. Finally, this chapter addresses only a fraction of the prominent forecasts regarding Brexit and ignores several of the most salient from the Leave campaign—for example, that leaving the EU would shore up NHS funding with Brexit savings.

In sum, Brexit is a timely and fascinating description and analysis of the 2016 UK referendum on EU membership. The analysis provides both a compelling explanation for what has happened and a framework for understanding future acts in this ongoing drama. Moreover, the argument advanced should prove helpful for understanding the politics surrounding current populist antagonism to the EU in other countries.