LONDON — From Brussels to Berlin to Washington, leaders of the Western democratic world awoke Friday morning to a blunt, once-unthinkable rebuke delivered by the flinty citizens of a small island nation in the North Atlantic. Populist anger against the established political order had finally boiled over.
The British had rebelled.
Their stunning vote to leave the European Union presents a political, economic and existential crisis for a bloc already reeling from entrenched problems. But the thumb-in-your-eye message is hardly limited to Britain. The same yawning gap between the elite and mass opinion is fueling apopulist backlash in Austria, France, Germany and elsewhere on the Continent — as well as in the United States.
The symbolism of trans-Atlantic insurrection was rich on Friday: Donald J. Trump, the presumptive Republican presidential nominee and embodiment of American fury, happened to be visiting Britain.
Asked where public anger was greatest, Mr. Trump said: "U.K. U.S. There's plenty of other places. This will not be the last."
Even as the European Union began to grapple with a new and potentially destabilizing period of political uncertainty, the British vote also will inevitably be seized upon as further evidence of deepening public unease with the global economic order. Globalization and economic liberalization have produced winners and losers — and the big "Leave" vote in economically stagnant regions of Britain suggests that many of those who have lost out are fed up.
Time and again, the European Union has navigated political crises during the past decade with a Whac-a-Mole response that has maintained the status quo and the bloc's lumbering forward momentum toward greater integration — without directly confronting the roiling public discontent beneath the surface.
But now the question is whether the dam has broken: Before breakfast on Friday, anti-Europe leaders in France and the Netherlands were rejoicing and demanding similar referendums on European Union membership.
From its outset, the European Union was a project of elites, one that, at times, moved forward without a clear popular mandate from the masses. Adopting the common currency was deeply controversial in some places, including Germany. The issue of democratic legitimacy has always hung over the unification project, since many significant steps were achieved through treaties that stirred considerable resistance in some countries.
European unity remained popular, particularly as the bloc delivered undeniable economic and social progress. But the class frictions beneath the project worsened in the past decade, as the European economy has been battered by recession and an uneven recovery.
It is not clear whether the message is getting through to more establishment leaders on both sides of the Atlantic, or what lessons they are taking from the shock of the British exit.
Perhaps the liberal Democrats in the House who staged a clamorous sit-in Wednesday night in Washington, while part of the system themselves, were channeling the populist anger of the American left in their willingness to break the rules to make a point about the need for gun control. In Brussels, many member governments appear divided between an instinct to respond to the British referendum vote by driving for greater integration among Germany, France and other core members of the bloc and a willingness to moderate their ambitions in recognition of public opposition.
European leaders were under pressure to reassure the European public, and the world, that the bloc was not at risk of unraveling. For decades, the European Union had moved forward, always expanding in size and influence. Britain has now reversed that trend.
"We're completely in uncharted territory," said Hans Kundnani, a Berlin-based expert in European politics at the German Marshall Fund of the United States.
Mr. Kundnani said the British vote exposed a contradiction at the core of the European project. European leaders define success as steering member states toward greater political and economic integration. And many of the bloc's inefficiencies and dysfunctions can be traced to the unfinished work of strengthening European institutions and achieving greater integration between member states in areas such as banking, finance, security and defense.
With or Without the E.U., Europe Is Still Connected
Britain's financial and military connections to the rest of Europe.
But public opinion is deeply skeptical of this "more Europe" agenda. Far-right populist leaders have stoked public anxieties and resurgent nationalism by lashing out against immigrants, while portraying the European capital, Brussels, as a bastion of political elites out of touch with the concerns of ordinary people. Far-left populists have demanded a re-examination of the neoliberal economics of free trade and limited regulation, while resisting efforts to deconstruct the social democratic welfare state.
"The E.U. robs us of our money, our identity, our democracy, our sovereignty," said Geert Wilders, the leader of the Dutch far-right Party for Freedom. "The elites want more E.U. They think they know better than the people. They look down on the people and want to decide in their place. They want us to be ruled by undemocratic, unaccountable bureaucrats in a faraway place like Brussels."
And permeating everything is the weak Continental economy and the crippling debt burden across Southern Europe.
"The E.U. is kind of trapped," Mr. Kundnani said. "On the one hand, the instinct will be to move ahead with further integration and reassure the rest of the world that the European Union is not unraveling. But that is very difficult because of the fault lines that exist."
How to Leave the European Union
British citizens voted Thursday on whether to leave the European Union. There are steps outlined for members wishing to withdraw from the bloc, but no country has ever left, so the process is uncertain.
He added: "They are trapped because moving ahead is very difficult. Moving backwards is the last thing they want to do. And the status quo is unsustainable."
Britain has always been a skeptical member of the European household. During the 1990s, Britain chose to keep the pound and not to join the countries sharing a common European currency, the euro. Many of the British concerns about the euro proved true, undermining the bloc's credibility, even as Britain has remained mostly insulated against the Continent's still unresolved euro crisis.
Before the referendum, some European officials portrayed Britain as an idiosyncratic case that should not be seen as a bellwether for the Continent. But that is a hard argument to make. In France, Ms. Le Pen's far-right National Front party is experiencing steadily rising popularity as the country prepares for national elections next year. In Germany, the anti-immigrant Alternative for Germany polled strongly in recent state elections.
Right-wing leaders in Hungary and Poland are hostile to immigrants, while critics say the governments of those countries are also rewriting national laws to undermine democratic checks and balances. In Italy, the anti-establishment Five Star Movement scored major victories last Sunday by winning mayoral elections in Turin and, more important, in the capital, Rome.
Portraits of a Nation Contemplating a 'Brexit'
Britons will make a momentous choice on Thursday that could matter more for their future than any ordinary election.
Donald Tusk, one of the European Union's top leaders, has started to talk about the risks facing the political establishment. At a speech last month before Europe's coalition of center-right political parties, Mr. Tusk cautioned his fellow political elites.
"Obsessed with the idea of instant and total integration, we failed to notice that ordinary people, the citizens of Europe, do not share our euro-enthusiasm," said Mr. Tusk, the president of the European Council, which comprises the heads of state of all the 28 member states in the bloc. "Disillusioned with great visions of the future, they demand that we cope with the present reality better than we have been doing until now."
Yet taking action may be difficult, since most analysts say the European Union is paralyzed by the coming national elections in 2017 in France and Germany, the two most powerful countries in the bloc. Neither the French nor the German government is eager to endorse sweeping initiatives for more European integration before the elections out of fear of a populist whipping at the polls.
"Europe is very divided and the main European country, Germany, has no will or skills to lead the union — and is approaching important national elections," said Lucio Caracciolo, the editor of the Italian geopolitical magazine Limes. "France is a country in crisis, while Italy has its own problems. I can't see who would assume a European leadership capable of producing a deeper integration process."
He added: "There is a very widespread rejection of politics everywhere. There is a similar mood in the United States, an antipolitical sentiment."
Few industries in Britain are likely to be more directly hit than the financial services industry in London. Damon Hoff, a hedge fund manager, said that he had voted to stay in the European Union, but that he understood the sentiments of those who had voted to leave.
"Europeans don't feel more prosperous," he said. "Europeans don't feel more empowered. And certainly the British don't."
He added: "You want to be part of something that continuously evolves. Does the European Union feel like it is evolving? No."
Donald Trump and the National Rifle Association aid and abet violence.