The international left is hailing the stunning performance of U.K. Labour Party Leader Jeremy Corbyn in Thursday’s election as a political and ideological victory. It’s easy to understand the enthusiasm from self-described socialists: Corbyn’s controversial ascendancy to the head of his party was a dramatic moment in European politics ― the centrist, finance-friendly approach of George W. Bush ally Tony Blair had been upended, and Labour was returning to the populist thinking that defined it for most of the 20th century.

But Corbyn’s victory is about much more than the internal dynamics of The Left. It is a critical event for anti-authoritarian politics more generally, one with implications that span the globe, and that carry a particular resonance in the United States in the age of Donald Trump.

Financial crises foment authoritarianism. This idea is not controversial in Europe, where authoritarian scars are still historically fresh. Stateside, many financial journalists intuitively grasp the connection between banking crashes and far-right politics, after witnessing the pattern in country after country. The idea dates back at least as far as the publication of John Maynard Keynes’ The Economic Consequences of the Peace in 1919, and has been repeatedly affirmed, including in a compelling 2015 study by three German academics.

But for American political science, the online wonk-industrial complex, and the cable news circuit, this is a difficult concept to grasp. As Donald Trump surged in the Republican primaries, a flurry of academic papers began making the rounds highlighting the moderately high median incomes of his supporters. These are still trickling out. They continue to serve as feature fodder for centrist publications and continue to be largely irrelevant to the political landscape. It doesn’t matter how rich the authoritarians are. Their key feature is their authoritarianism.

We have had few financial crises in the United States since the Great Depression, and our political thinkers are accustomed to grappling with aristocratic conservatism, not authoritarianism. Aristocratic conservatism ― the type espoused by House Speaker Paul Ryan and establishment Republicans of the past 50 years ― seeks to protect the financial interests and social status of the wealthy. Banking elites want low capital gains taxes, but they are in many ways more protective of their position on top of the American social hierarchy. Even as he scuttled prosecutions for financial fraud and protected bonuses for bailed-out bankers, former President Barack Obama prompted hysterical denunciations from Wall Street by casually dismissing “fat cat bankers” in a single TV interview early in his first term.

The Democratic Party can sometimes defeat aristocratic conservatives by publicly shaming them as extremists. Aristocratic conservatives are sensitive to elite social pressure and respond to attacks on their dignity. This was a key plank of Hillary Clinton’s 2016 general election strategy, and in some ways, it worked: Clinton really did win over a big chunk of millionaires who had previously voted Republican.

But shame is a terrible strategy for defeating authoritarian candidates after a financial crisis. Banking meltdowns don’t unleash a wave of aristocratic sympathy. They cause widespread, unfair suffering and create tremendous uncertainty. People lose their jobs and homes through no fault of their own. Even working families who survived the 2008 crash relatively unscathed did not do so without having to confront new psychological strains. Millions of people who kept their jobs had to come to the aid of family members who did not. The prospect of economic ruin was always right around the corner.

Authoritarians exploit this uncertainty by promising stability, order and safety. This is not a mathematical equation guaranteeing higher incomes. It is a social rebellion against the governing aristocracy that has just failed and ― even in the most just and perfect bank rescue ― enjoyed the political prioritization of its own interests over the needs of the broader citizenry.

In the wake of a financial crisis, the public does not interpret centrist politics as an appeal to moderation or reasoned debate. It sees centrism as an attempt to rehabilitate the legitimacy of the aristocracy which has just pushed the country into disaster. “Countrymen, I have been approved by the finest minds of the old order as an eminently reasonable leader!” is a poor slogan when measured against “I will crush your enemies and restore your glory!”

A much better pitch? “I am on your team and will protect you.” This works very well with promises to expand and improve social welfare programs. “I will break the cheating aristocrats who did this to you” can also be effective. In 1932, Franklin Delano Roosevelt put the Democratic Party in power for only the third time since the Civil War by campaigning on a combination of both messages.

Whatever the slogan, anti-authoritarian politicians need to make a clean break with what failed and offer a psychological alternative to authoritarianism’s call for order through violence and suspension of civil liberties.

The specific policy agenda is important ― politicians need good ideas that people actually like. Corbyn appears to have significantly boosted the youth vote by promising to abolish college tuition fees entirely. But policy mostly functions as a guidepost for voters. A leader’s tone and presentation matter just as much ― the point is to project a sense of safety and community. Corbyn nailed that part, too. When May called the election, she and the Conservatives believed Corbyn’s left-wing priorities would alienate him from voters. His stump speeches did the exact opposite.

Hillary Clinton got some of the policy right in her 2016 run. Bernie Sanders ran to her left, of course, but Hillary’s debt-free college plan was in some respects more progressive than Bernie’s tuition-free deal. Her positioning, however, was awful. Campaigning to boost the minimum wage? Good. Insisting that a $12 minimum wage was much more responsible than a $15 minimum wage, then waffling and saying maybe $15 was fine, then trying to talk about something else? That was pretty bad. Getting paid millions of dollars to give private speeches to Goldman Sachs and other Wall Street firms? That was catastrophic.

Trump is the American strain of the authoritarian virus that has infected much of Europe. In France, its standard-bearer is Marine Le Pen. In Greece, it is the neo-Nazi Golden Dawn party. Finland has the True Finns; Hungary has Jobbik. In the U.K., this faction was represented by Nigel Farage and the U.K. Independence Party, which won 4 million parliamentary votes in 2015 and successfully mobilized a campaign to push their country out of the European Union by demonizing refugees and promising better health care for native Britons.

Farage is still at it. During a Fox Business interview with Maria Bartiromo last week, he raised the prospect of mass “internment” of “thousands” of terror suspects. But under May, the chief vehicle for authoritarian politics in the U.K. has become the Conservative Party. She has embraced Farage’s Brexit cause and floated the repeal of human rights laws in the name of stability in opposition to Corbyn’s “weak” approach to terrorism. On Thursday night, UKIP was decimated, its vote split between the new ethno-nationalist haven in the Conservatives, and the populist alternative offered by Corbyn’s Labour party.

The same union of authoritarian insurgents and the aristocratic old guard is taking place in the United States. After campaigning as an authoritarian populist, Trump has filled his administration with Goldman Sachs alums and is embracing the aristocratic economic agenda of Paul Ryan’s Republican Party.

And the Republican aristocracy, with a few Never-Trumper exceptions, is reciprocating. Just ask Paul Ryan about James Comey’s Senate testimony. Then ask him about Dodd-Frank.

Corbyn made significant gains where nearly every political expert in Europe expected him to march off an electoral cliff. He did so by abandoning dyed-in-the-wool aristocratic Tory voters, energizing new, young Labour voters with policy, and making a direct psychological challenge to authoritarian appeals.

There’s a lesson there for the Democratic Party. It can be the party of the Good Aristocrats, or it can be the Anti-Authoritarian Party. But it can’t be both.