LONDON — The British have given the world’s political, financial and business establishment a massive kick in the teeth by voting to leave the European Union, a historic decision that will plunge Britain into uncertainty for years to come and reverses the integration on which the continent’s stability has been based.

Warnings by President Barack Obama, Britain’s political leaders and the International Monetary Fund about the dire consequences of a British exit proved useless.

If anything, they goaded a mood of defiant anger against these very elites.

This resentment has its roots in many things but may be summed up as a revolt against global capitalism. To heck with the experts and political correctness was the predominant mood in the end. A majority of Britons had no time for the politicians that brought the world a disastrous war in Iraq, the 2008 financial meltdown, European austerity, stagnant working-class wages, high immigration and tax havens for the super-rich.

That some of these issues have no direct link to the European Union or its much-maligned Brussels bureaucrats did not matter. It was a convenient target in this restive moment that has also made Donald Trump the presumptive Republican nominee — and may now take him further still on a similar wave of nativism and anti-establishment rage.

David Cameron, the British prime minister prodded into holding the referendum by the right of his Conservative Party, said he would resign, staying on in a caretaker capacity for a few months. This was the right call, and an inevitable one. He has led the country into a debacle.

The pound duly plunged some 10 percent to its lowest level since 1985. Global markets were rattled. Mainstream European politicians lamented a sad day for Europe and Britain; rightists like Marine Le Pen in France exulted. The world has entered a period of grave volatility.

Ever-greater unity was a foundation stone since the 1950s not only of peace in Europe, putting an end to the repetitive wars that had ravaged generations of Europeans, but also of the global political order. Now all bets are off. A process of European unraveling may have begun. A core assumption of American foreign policy — that a united Europe had overcomes its divisions — has been undermined.

Geert Wilders, the right-wing anti-immigrant Dutch politician, promptly tweeted: “Hurrah for the British! Now it is our turn. Time for a Dutch referendum!” The European Union is more vulnerable than at any point since its inception. The sacred images of old — like French President François Mitterrand and German Chancellor Helmut Kohl hand-in-hand at Verdun — have lost their resonance. The travails of the euro, the tide of immigration (both within the European Union from poorer to richer members and from outside), and high unemployment have led to an eerie collective loss of patience, prudence and memory. Anything but this has become a widespread sentiment; irrationality is in the air.

The colossal leap in the dark that a traditionally cautious people — the British — were prepared to take has to be taken seriously. It suggests that other such leaps could occur elsewhere, perhaps in Trump’s America. A Trump victory in November is more plausible now because it has an immediate precedent in a developed democracy ready to trash the status quo for the high-risk unknown.

Fifty-two percent of the British population was ready to face higher unemployment, a weaker currency, possible recession, political turbulence, the loss of access to a market of a half-billion people, a messy divorce that may take as long as two years to complete, a very long subsequent negotiation of Britain’s relationship with Europe, and the tortuous redrafting of laws and trade treaties and environmental regulations — all for what the right-wing leader Nigel Farage daftly called “Independence Day.” Britain was a sovereign nation before this vote in every significant sense. It remains so. Estrangement Day would be more apt.

The English were also prepared to risk something else: the breakup of the United Kingdom. Scotland voted to remain in the European Union by a margin of 62 percent to 38 percent. Northern Ireland voted to remain by 56 percent to 44 percent. The Scots will now likely seek a second referendum on independence.

Divisions were not only national. London voted overwhelmingly to remain. But the countryside, small towns and hard-hit industrial provincial industrial centers voted overwhelmingly to leave and carried the day. A Britain fissured between a liberal, metropolitan class centered in London and the rest was revealed.

Europe’s failings — and they have been conspicuous over the past decade — are simply not sufficient to explain what Britain has done to itself. This was a vote against the global economic and social order that the first 16 years of the 21st century have produced. Where it leads is unclear. The worst is not inevitable but it is plausible. Britain will remain an important power. But it will punch beneath its weight. It faces serious, long-term political and economic risk.

Anger was most focused on the hundreds of thousands of immigrants coming into Britain each year, most from other European Union nations like Poland. Farage’s U.K. Independence Party, abetted by much of the press, was able to whip up a storm that conflated EU immigration with the trickle from the Middle East. Wild myths, like imminent Turkish membership of the European Union, were cultivated. Violence entered the campaign on a wave of xenophobia and take-our-country back rhetoric.

In this light, it is not surprising that Trump supporters were delighted. Sarah Palin welcomed the “good news.” One tweet from a supporter read: “I’m thrilled with U.K. 1st step — time 4 all the dominoes 2 fall, every country to leave & end the E.U.”

Trump arrived in Britain on Friday, a timely visit. He said the vote to quit the EU was “a great thing” and the British “took back their country.” He did not say from whom, but the specter of our times is a dark, controlling global force stealing national identity.

It is quite likely that Cameron’s successor will be Boris Johnson, the bombastic, mercurial and sometimes fact-lite former London mayor with his trademark mop of blond hair. Johnson was a leader of the campaign for “Brexit”; he may now reap his political reward. The Era of the Hair looms.

Timothy Garton Ash, the historian, paraphrasing Winston Churchill on democracy, wrote before the referendum that: “The Europe we have today is the worst possible Europe, apart from all the other Europes that have been tried from time to time.”

It was a wise call to prudence in the imperfect real world. Now, driven by myths about sovereignty and invading hordes, Britain has ushered in another time of treacherous trial for the European Continent and for itself.

My nephew wrote on Facebook that he had never been less proud of his country. I feel the same way about the country I grew up in and left.

CORRECTION: In a recent column about the Orlando nightclub killings, I included an Israeli journalist’s tweet about Michael Oren, a former Israeli ambassador to the United States, that misquoted him as saying: “If I were Trump, I’d emphasize the Muslim name, Omar Saddiqui Mateen. This changes race.” In fact, this was a paraphrase of Oren’s comment. Translated from Hebrew, the comment was: “If I were Donald Trump I’d come out the minute the FBI decided to start leaking this morning that we are talking about a man who acted out of Islamic motives, with connections. First of all the name itself, Omar Siddiqui Mateen, a Muslim name, the son of immigrants from Afghanistan, who apparently was somehow in touch with extremist Islamic organizations. This already has a significant influence on the race for the presidency.”

The European Union is more vulnerable than at any point since its inception.