Trump Victory Draws Parallels With Brexit Referendum

Instead, the establishments in Washington and London were dealt a bloody nose. The two campaigns reflected similar rhetoric: outsiders attacking a cozy clique of insiders in league with bankers and big business, the idea of ordinary people taking back control, and a rejection of immigration. The shock was magnified by the 21st-century phenomenon of social media in which two diametrically opposing worldviews were separated during the campaigns and rarely overlapped.

The U.S. and U.K. campaigns traveled a similar arc: Like with U.K. “Leave” voters, Trump supporters were consistently underestimated by polls, as was the extent to which they’d turn out. Though pollsters predicted a tight vote before Brexit, many were stunned by the outcome. U.K. bookmakers put long odds on both a vote for Brexit and a win for Mr. Trump.

The slogans and catchphrases around the votes also often echoed each another: Hillary Clinton campaigned with the message “Stronger Together,” while the losing Remain campaign promoted a “Britain Stronger in Europe.”

Mr. Trump ended his campaign with the suggestion that Tuesday would be “Independence Day.” Nigel Farage, head of the anti-EU UK Independence Party and an outspoken champion of Britain’s exit from the bloc, said the same after the June 23 U.K. referendum. Both Mr. Trump and Mr. Farage spoke of “taking back control.”

Mr Trump also employed Cambridge Analytica, the U.S. arm of a British behavioral research and strategic communications company called SCL Group Ltd. that also assisted the Leave.EU campaign.

In London, architect Julian Tollast said he was still coming to terms with the implications of the U.S. vote. “I woke up halfway through the night, looked at my phone, and thought ‘Oh dear, this is going the same way the Brexit vote went,’ ” said Mr. Tollast, who supported staying in the EU in Britain’s June referendum. “The media and the polls got it completely wrong again.”

Anthony Wells, director of political and social research at U.K.-based pollster YouGov PLC, said polling firms would need to plow resources into persuading a broader swath of voters—hard-to-poll people who don’t normally vote—to participate in polls if they are to improve the results. “Pollsters around the world are suffering these same problems,” he said.

In broad terms, the electoral maps on both sides of the Atlantic looked similar. Voters in major urban areas seen as benefiting from globalization voted for Hillary Clinton and staying in the EU. Rural and Rust Belt voters, and those in small towns and cities, voted against those choices.

Support for Brexit and/or Mr. Trump was underpinned by white working-class voters. Mr. Trump—who at one point called himself Mr. Brexit and vowed to deliver “Brexit times 10”—drew a direct comparison, saying that the momentum behind Brexit and his movement were both fueled by frustration over immigration.

“Once again, opinion polls, academic forecasters and much of the mainstream media have collectively failed to identify the frustration and anger among mainly white and typically less-well educated” people who feel threatened by globalization and growing ethnic minorities, said Matthew Goodwin, a politics professor at the University of Kent in England known for his work on euroskepticism.

Jeff Platt, a 33-year-old from Manchester, England, who voted for Brexit, said he saw the Brexit vote and the U.S. election as being driven by people who felt ignored. “Ultimately, it’s the whole blue-collar protest vote, and on a large scale,” said Mr. Platt, who works at a bank.

Mr. Farage hailed Mr. Trump’s success as even bigger than Brexit. “The revolution continues,” he said Wednesday. “It’s been a remarkable year, and I think that Trump has scored an extraordinary victory.”

Both votes had their eureka moments. In the Brexit vote, it came with the pro-Brexit result from Sunderland, an old industrial town in the northeast of England that has benefited from recent investment in the car industry. In the U.S., it came when Florida was declared for Mr. Trump.

But the fundamental message is potentially more significant: voters in two Anglo-Saxon countries appear to have rejected the causes of free trade and open markets of which their governments have long been the strongest champions.

In the same year, the American and British electorates have signaled that they think international economic integration has gone too far and their political establishments have let them down.

In some ways, the two countries seem unlikely candidates for an anti-globalization backlash. Despite being hit badly by the financial crisis, both now have unemployment rates below 5%.

Yet average incomes have only recently recovered to their levels of 10 years ago since the financial crash. And economists say​that, because some high-earners are enjoying rising incomes,​the average-income measure may be masking the deterioration in living standards being felt by the bottom 50%.

Polling also suggests a cultural dimension in both places: White indigenous populations seeking in the face of economic insecurity to defend their share of a slow-growth economy against minorities and immigrants.

“We’re in the great unknown,” said Crispin Blunt, a Conservative lawmaker in Parliament. “What attachment is there to the rules of the liberal, international order that has pretty much dominated how the West has conducted business since the end of Cold War?”

—Nicholas Winning and Jason Douglas contributed to this article.

Write to Jenny Gross at jenny.gross@wsj.com and Stephen Fidler at stephen.fidler@wsj.com