One of the disturbing motifs of Donald Trump’s campaign for president of the United States was his penchant for attracting unwanted—or at least unhelpfully revealing—endorsements. In the final days, for example, the Crusader, the newspaper of the Ku Klux Klan, lent the Republican nominee its backing. That echoed the support that had been voiced already, and repeatedly, by America’s best-known former Klansman, David Duke, who positively brimmed over with enthusiasm for Trump—admiration that the candidate was slow to disavow.

The habit held even after Trump won his improbable victory on Tuesday. In Moscow, the Duma burst into applause as Russian parliamentarians celebrated Trump’s victory (and no less heartily, one suspects, Hillary Clinton’s defeat). Unsurprisingly, they were in lockstep with Vladimir Putin, who was one of the first world leaders to congratulate the new president-elect. Putin was swiftly joined by the Dutch nationalist Geert Wilders, who said, “The people are taking their country back. So will we.” And by the French ultra-rightist Marine Le Pen, who applauded Trump for proving that “the political and media elite” could be put in their place. Not to be left out, the Hungarian nationalist Viktor Orbán declared, “Democracy is still alive.”

Perhaps you can see a pattern here. Europe’s most strident populists and chauvinists are thrilled by the Trump victory. They see in him a kindred spirit, a European-style white nationalist with a New York accent. In their view, Trump’s success, storming the citadel of the world’s most-watched democracy, confirms that their current surge is no fringe phenomenon, but a rising—and global—wave. As Le Pen’s chief strategist put it, addressing the established political class, “Their world is collapsing. Ours is being built.”

They were not the only non-Americans to applaud Trump’s win. Besides the European white right, his admirers included a wide assortment of authoritarian leaders. Those parts of the Turkish press sympathetic to Recep Tayyip Erdogan expressed their pleasure at Trump’s upset win (perhaps that’s just Erdogan’s way of welcoming in a new member to the International Fellowship of Strongmen). Iran’s Supreme Leader was also pleased to see turmoil in the US (and, no doubt, to see the smile wiped off Clinton’s face).

Meanwhile, a consultant now advising a government in one of the Persian Gulf states called to tell me that undemocratic regimes in his part of the world were surprisingly glad to see Trump prevail, too. His explanation: tired of lectures from a US permanently on its moral high horse, these governments were tickled by the prospect of America being led by a demagogue. “It shortens the moral distance between them,” he said.

As telling as the cheers Trump received from the chauvinist and autocrat communities was the mix of disappointment, apprehension, and revulsion his win provoked in nearly everyone else. A pre-election global poll found that, had the rest of the world had a vote, every country on the planet would have chosen Clinton—every country except Russia, that is. The Daily Telegraph of Australia neatly distilled the global response to his upset victory with its front page headline: “WTF.”

More stately, but no less pointed was the word of congratulation sent by the de facto leader of Europe, Angela Merkel. The German chancellor delivered a barely-coded scolding to Trump, reminding him that the US-German relationship rested on shared values such as “democracy, freedom, respect for the law and for human dignity irrespective of origin, skin color, religion, gender, sexual orientation or political conviction. On the basis of these values, I offer the future president of America, Donald Trump, a close working relationship.” Translation: if you don’t honor those principles—and start to make amends with all those groups you have offended during the campaign—we’re not friends. (Whatever communication French President Francois Hollande sent to Trump Tower, it’s unlikely to have repeated his admission in August that some of the Republican’s behavior made him “want to retch.”)

But the overwhelming sentiment animating European and global responses to the US election is fear. In the chancelleries of Europe, it already has two distinct forms: fear over what Trump will do and fear over what his victory might mean closer to home.

Start with the first category. America’s allies wanted Hillary Clinton to win partly because she was a known quantity and partly because she was a clear believer in the international system of treaties, organizations, and alliances—institutions such as NATO, the UN, the Nuclear Non-Proliferation Treaty, the WTO, the Geneva Conventions, the G20, and the like. Trump is a total unknown and has cast aspersions on several of these institutions during his campaign.

It’s telling that in London the person who probably knows Trump best is not in government at all: it’s Nigel Farage, the arch-campaigner for Brexit who doesn’t even sit in the House of Commons, but who made a guest appearance as a warm-up man at a Trump rally in August. In prime minister Theresa May’s team there is no one who has any relationship at all to the new US president.

It’s not just that they don’t know him. It’s also that the one thing they do know is that he’s unpredictable. That frightens diplomats who value stability above all. The rumors of possible cabinet appointments have not helped soothe anxious diplomatic brows either. That both Newt Gingrich and John Bolton have been tipped for the State Department will have had foreign ministries in several capitals trembling. Both are known as fire-breathers. (If Sarah Palin, who does have a global reputation of a sort, gets a cabinet post, that will trigger yet more angst.)

Beyond personnel, European governments are even more fearful of Trump’s foreign policy. They worry that he will cosy up to Russia, which they regard as aggressive and disruptive. (Russia has already extended a hand to Trump, perhaps to press its advantage.) They worry that Trump’s doubts over NATO, publicly voiced in a New York Times interview in July, could undermine the foundations of that alliance which has held the peace since 1945. His questioning of Article 5—which commits each member state to come to the defense of another, should it come under attack—sent tremors through the Baltic states. If Putin does not believe Trump would defend, say, Latvia from invasion, then what’s to stop him from doing so?

There is further concern over Trump’s curious strain of bellicose isolationism: threatening “to bomb the shit” out of ISIS, but also to turn America inward. They worry that Trump will have no interest in or understanding of the indispensable nature of US leadership in, say, the IMF or the G20. They shudder at reports that he plans to cancel the Paris climate change agreement on his first day in office. Put simply, they believe that the world cannot function safely without US leadership—and they are not sure Trump is willing or able to provide it.

But the second worry is more self-centered. Leaders in Europe and the wider West fear that Trump’s win, just months after Brexit, is the second victory for an uncontrollable populist revolt that has erupted on both sides of the Atlantic, one animated by opposition to globalization and to establishment elites, variously defined—as well as to immigrants and assorted other targets, often Muslims. The wave swept Britain out of the European Union in June and has taken a con artist, bigot, and self-confessed sexual predator to the White House in November. Elections are coming in Austria next month, a re-run involving a far right candidate, and in France, Germany, and Holland in 2017, all countries with increasingly robust ultra-nationalist parties. Every mainstream candidate is looking at the defeated Hillary Clinton—so qualified, so experienced, so establishment—and wondering if he or she might be next.