A S FAR AS British politics is concerned, Brexit is the defining issue of our time. Yet even intelligent people cling to feeble explanations of why it happened. Remainers present it as a revolt of the know-nothings, despite the fact that a third of graduates voted Leave. Brexiteers counter that it was a revolt of the people against the elites, despite the fact that Brexit was popular among rich retirees in the shires, and that many of the campaign’s leaders went to expensive private schools. Others implausibly cite one-off factors, such as Russian interference or Jeremy Corbyn’s Europhobia.

Two new books offer much more intelligent explanations of Brexit. They matter—not just because intelligent explanations are preferable to foolish ones, but also because the subject is still a live one, with millions of people hoping to reverse the referendum and the Conservative Party fighting a civil war about what sort of Brexit to embrace. “Whiteshift”, by Eric Kaufmann, is a monumental study of ethno-demographic change and the rise of populism across the rich world. “National Populism”, by Roger Eatwell and Matthew Goodwin, is a fact-filled survey of the revolt against liberal democracy. Both books range far beyond Brexit and Britain. But in doing so they put a parochial debate in a much bigger context.

Mr Kaufmann, a professor at Birkbeck College, London, argues that Brexit is an example of how anti-immigration populism can suddenly punch through from the margins of politics into the mainstream, threatening the economic interests that cosmopolitan elites care about. The foreign-born share of Britain’s population remained under 2% until the 1950s and stood at 6% as recently as 1991. Then a number of things happened. Immigration surged. The Labour government tried to redefine Britishness to mean support for cosmopolitan liberalism (according to Andrew Neather, one of Tony Blair’s speechwriters, some in the party wanted to use mass immigration to “rub the Right’s nose in diversity and render their arguments out of date”). The attacks of September 11th 2001 and July 7th 2005 put the question of Islamist terrorism at the heart of politics. Successive governments failed to keep their promises to reduce immigration. And a long-simmering row within the Conservative Party triggered a referendum on Brexit that also involved profound issues of national identity, giving voters a unique opportunity to express worries that had been festering for decades. A poll two months after the referendum showed that 87% of Leavers wanted to reduce immigration and 40% thought it the top issue facing the country.

Mr Kaufmann’s decision to focus on “whiteness” is questionable when it comes to understanding Brexit and perhaps even when it comes to understanding Trumpism (28% of Latinos voted for Donald Trump in 2016). The big surge in immigration after 2004 came from whites, when eight eastern European countries were admitted to the European Union. Large numbers of south Asians in places such as Birmingham, Bradford, Luton and Slough voted for Brexit because they worried that Poles and Romanians were taking “their” jobs and using “their” public services. But Mr Kaufmann is undoubtedly right that it is impossible to understand Brexit—or populism in general—without examining the way that mass immigration has discombobulated established populations.

Messrs Eatwell and Goodwin also emphasise the importance of immigration, which they somewhat ominously classify under “destruction”, one of four Ds that they believe explain populism. The second is distrust, of established elites. Some 58% of Britons who thought that politicians “do not listen to people like me” voted for Brexit, compared with only 37% of people who thought they did listen. About 2.8m habitual non-voters, who had given up on politics during the Blair-Cameron years of identikit politicians with interchangeable policies, turned out to vote Leave. The third D is deprivation. It is important not to exaggerate this problem. Many people, rich and poor, voted for Brexit because they worried about democracy and accountability. But a growing feeling of both absolute and relative deprivation nevertheless tipped the balance for significant groups of voters, particularly in Labour territory, where local MP s fought a losing battle against the Brexit tide.

The fourth D is the “dealignment” of politics, meaning the abandonment by voters of their usual party. This is the most counterintuitive of the authors’ claims when it comes to Britain. In the election last year, Labour and the Tories won 82% of the vote, their highest share since 1970. But the potential for dealignment is there. In 2015 and 2017, 43% and 32% of voters respectively changed their votes from the previous election. Brexit cuts like a knife through both main parties: Labour represents the most passionately pro-Remain constituencies in the country and the most passionately pro-Brexit ones.

The revolts to come

What does this mass of research tell us about the future? An immediate lesson is that the political elite should not take the decision to re-fight the 2016 referendum lightly if the opportunity presents itself. Millions of people who voted for Brexit precisely because they felt that their opinions were being ignored by the establishment could be dangerously radicalised if a second vote went narrowly in favour of Remain. A longer-term lesson is that, Brexit or no Brexit, nationalist populism will be an important part of British politics for decades. Many feel the odds are stacked against them. The post-industrial economy combines large amounts of disruption with slow growth. Culture is dominated by preening elites who not only think they are cleverer than the average person but also that they are more virtuous. Brexit is an example of what can happen if politicians refuse to deal with popular fears about emotive subjects before they become toxic. It is vital that the political class, not just in London but across the West, and not just in legislatures but among the broader establishment, learns the right lessons from this failure.