Matthew J. Goodwin is Professor of Political Science at the University of Kent and Senior Visiting Fellow at Chatham House. He is author of Revolt on the Right: Explaining Public Support for the Radical Right in Britain.

LONDON—Don’t underestimate the power of nativist populism. That’s the harsh lesson we in Britain learned less than four months ago, when Brexit blew up in our faces and confounded nearly every prediction. It’s one the Austrians and French are learning even now, as they keep counting out (then are forced to count back in) right-wing populist backlashes to the establishment. And it’s the lesson that American pundits who are already predicting a comfortable victory for Hillary Clinton over the embattled Donald Trump—if not a historic landslide—should take on board before they start relaxing too much in the next few weeks.

Of course, every election, and country, is unique. And with little more than 20 days left until America elects its next president, there is reason for the new sense of confidence in the Clinton camp. In recent weeks, Trump has been engulfed by scandal, and Clinton’s position has strengthened considerably in the polls.


But recent elections outside the United States should check too much complacency in the Clinton camp, especially when the side that is perceived to be losing is preaching nativist populism to voters who have been economically left behind and feel culturally under threat from ethnic change. Voters, in other words, who are especially motivated to vote for change. Less than four months ago the United Kingdom held a national referendum on whether it should exit the European Union, known as Brexit. Ahead of that contest, the betting markets, pundits and media were united in predicting a comfortable win for the pro-EU side, who wanted the U.K. to remain in the EU. Most of the polls, too, put “Remain” ahead (especially polls conducted by telephone), while the few online polls that suggested a Brexit victory were dismissed as rogue outliers riddled with sampling errors. Pundits pointed to the unfavorable ratings of leading Brexiteers like Nigel Farage who, they argued, were too divisive for Brexit to win. Others pointed to how even most voters accepted there did not seem to be much of a plan for life after Brexit. The Remain camp, we were also told, had the superior ground game—it seemed to be knocking on more doors, had more offices and had a developed strategy for targeting young university towns.

These assumptions continued to guide the national debate right up until the contest itself. In the prediction markets, throughout the final week of the campaign, the percentage chance that Remain would win did not fall below 75 percent. In the final days, seven polling companies issued their “final” polls, none of which forecast the eventual result. In three cases, the result was within the margin of error, though only one had put Brexit ahead, while the remaining four had overestimated support for Remain. Every single poll, noted the British Polling Council, even those within sampling error, had overstated support for Remain. Even on the day of the vote, three polls put Remain ahead, one by a striking 10 points.

The betting markets were just as confident; on the morning of the referendum, they put Remain’s chance of victory at 76 percent and, by the close of voting, at 86 percent. When you asked voters who they expected to win, it was the same story; in the final 24 hours of the campaign, only 27 percent expected Brexit to triumph. Those who sought to keep Britain in the EU, having recruited President Barack Obama to their cause, expressed relief. An anxious Prime Minister David Cameron was told to relax.

Almost everyone was proved wrong by the massive turnout of Brexit voters, who had been derided by established politicians as loons and racists and who were not expected to be organized, especially at the polling stations. “Leave” won 52 percent of the vote across the U.K., and nearly 54 percent in England. This figure rocketed higher in poorer industrial and rural communities that had been cut adrift by globalization and felt under threat from unprecedented levels of immigration—the analogue to many Trump voters today (as even Trump himself has suggested, tweeting that he would soon be known as “Mr. Brexit”). Support for Brexit reached striking levels among those same groups of voters who are now backing Trump—nearly 60 percent among voters on low incomes, over 70 percent among manual workers and 75 percent among people with no qualifications. In forgotten England, the anti-elite and anti-immigration message had spread like wildfire. The left behind mobilized in a big way.

Turnout rates among poorly educated white voters threw cold water on the earlier claim that the angry white man would not show up, that he would be pushed aside by young cosmopolitans and the big cities. Overall turnout was high, at 72 percent, the highest for any U.K.-wide vote since 1992. Subsequent analysis of how this affected the vote suggests that Brexit won by mobilizing people who never normally vote, something that Trump hopes to emulate. The unexpectedly high turnout, especially in blue-collar communities, is why turnout models in the polls that were based on turnout at previous elections performed poorly; they failed to account for the mobilization of unlikely voters. Turnout was much higher among the Brexit-voting over-55s and strikingly lower among young voters who had promised to vote. Some estimate that whereas 64 percent of young people who were registered to vote did vote, this figure was 74 percent among people ages 55 to 64 and 90 percent among those ages 65 and above. In the aftermath of the Brexit victory, a petition emerged to overhaul the result through a second referendum. The largest number of signatures were in young and trendy areas like the London districts of Camden and Hackney, where voters had failed to turn out when it mattered.

The Brexit vote is a powerful reminder not only of how identity can trump economics but also of how supporters of populist insurgents are often more loyal than many think. While the pro-EU side had focused relentlessly on dry arguments about jobs, wages and appeals to economic self-interest, Brexit was pushed over the line by a campaign that tapped into an intense cultural angst among blue-collar, left behind and older voters. The core message of “Take Back Control” had resonated strongly among these voters who had long felt cut adrift from mainstream politics and under threat from rapid ethnic change. That culture was as important as economics was reflected in the fact that it was in communities that had experienced the most rapid ethnic change over the past 10 years where support for Brexit was often strongest. Presented with an opportunity to reassert their conservative values and disdain for a liberal mainstream, they took it. The intense power of this identity angst should have been diagnosed given that ahead of the referendum most voters readily admitted to pollsters that they would be willing to suffer an economic hit if, in turn, it meant they had greater control over borders and immigration. Political and media elites failed to diagnose the simmering anger and mistakenly believed that it could be soothed with appeals to rational choice.

In the U.S. election, it is clear that the strategy of the Trump campaign is to rile up the passions of America’s disaffected in the same way—to the point where many people at his rallies are now saying they’re doubly motivated to go to the polls to ensure that the election isn’t “rigged,” as the candidate himself has been urging them to do.

Other experiences in Europe underline the durability of support for right-wing populists. Since the 1980s, the media and liberal progressives have written off anti-immigration and anti-elite populist parties, but they never go away and have only accumulated support. In Austria, since the mid-1980s, the populist xenophobic Freedom Party has sustained a strong following; today it is on the verge of possibly winning the presidential election in December. In France, Marine Le Pen is currently forecast to reach the final second-round of the presidential election next spring despite her party being widely written off after her father was defeated in the same contest in 2002 and then saw a drop-off in support in 2007. This durability flows from an economically disaffected, socially conservative, white, less educated and male electorate that has mobilized despite talk of its members' alienation and apathy.

It is also worth noting another contest in Britain: In 2015, conventional wisdom had again mistakenly told us that the progressive, social democrat Labour Party would likely triumph. The polls and commentariat were united in claiming that no party would secure an overall majority, that Britain was thus headed for a hung parliament and that—most likely—there would be a coalition headed by the uninspiring but nonetheless competent Labour leader, Ed Miliband. Labour, we were told, also had a superior ground game (rooted in Labour’s promise to hold “four million conversations with voters in four months”). When some of the world’s most renowned political scientists gathered at a conference to share their increasingly sophisticated forecasts of the election, not a single one predicted the outcome—a majority Conservative government. The polls, too, had been wrong. A subsequent inquiry revealed they had consistently overestimated Labour support and were among the most inaccurate since election polling had begun in 1945. Their samples had too many "easier to reach" Labour voters and not enough harder-to-reach older and more socially conservative voters.

Donald Trump will most likely fail to win the presidency, not least because the mechanics of the race differ from those contests above in important ways. The electoral college stacks the deck against the Republicans; there is a sharp gender gap in current voting intention (which was not evident at Britain’s EU referendum); and the Trump candidacy is perhaps the most divisive in modern American history. But at the same time, recent history from across the Atlantic reveals why you should never dismiss the appeal of a populist insurgency, place blind faith in the polls and forecasts nor assume that populist voters will not mobilize when—in their eyes—it matters most. Anger goes a long way at the polls. Trump is still the underdog, but those who claim to be experts would still be foolish to completely write off the power of the revolt on the right.