BRUSSELS — Here’s the word from Europe: A lot of diplomats, elected officials, intellectuals and European Union officials are pretty freaked out about Donald Trump.

After nearly a year of being told by their U.S. counterparts that the bombastic billionaire had no chance of winning the Republican presidential nomination, here he is, defying conventional wisdom and even that oracle of oracles, Nate Silver of FiveThirtyEight fame, who assured the world last August that Trump had only a 2 percent chance of wining the primaries.

What, many ask, is going on?

That was the question on nearly everyone’s lips when I was in Brussels, Paris and Belgrade, Serbia, at the end of last month with co-presenter Sewell Chan, London-based international editor at The New York Times, to help explain the U.S. political scene to our worried trans-Atlantic partners. It was a cultural exchange trip hosted by the German Marshall Fund of the United States, with some events convened by the U.S. Mission to the European Parliament and others by EU40 (a group of young European Parliament members) or the University of Belgrade’s Faculty of Political Science.

How could this man – so obviously unprepared and unqualified for the office he seeks – be on the verge of winning the nomination of what was once the Party of Lincoln, asked the parliamentarians and economists, bureaucrats and journalists, attorneys and businesspeople who came to the events? Could he win the general election? If he did, what would his foreign policy look like?

The concern was palpable. The United States, though diminished since 2001, is still the world’s only superpower, a vital EU trading partner and the presumed guarantor of European security against the renewed territorial ambitions of Russia. Americans might feel they can safely ignore political developments in Paris, London or Berlin, but Europeans don’t have that luxury when it comes to us.

Their worries centered on two things: the potential effect on world economic growth if Trump were to scale back free trade agreements, and whether he has the maturity and self-control to be entrusted with the launch codes of a nuclear arsenal capable of destroying the world.

Here, for what it’s worth, is what I told them.

Of the 17 people who ran for the Republican nomination, Trump was the only one who failed to voice the laissez-faire mantra, that lower taxes, less government and less regulation will, axiomatically, bring more freedom. Trump hasn’t promised to cut capital gains, introduce a flat tax, cut government programs or roll back regulations. On the contrary, he says he’s against global trade agreements, the free-ish movement of labor into the country and “hedge fund guys” who are “getting away with murder” in the tax code.

Instead, he’s championed a group of people who’ve seen their standard of living decline in the face of globalization: the white working class, whose economic interests haven’t been represented by either party in two generations. He claims he’ll bring back manufacturing and make their America great again. They’ve responded enthusiastically, although Trump is about as far from conservative Christian family values and Republican free market orthodoxy as one can get. They’re the warm water fueling the Trump hurricane.

The downside is that Trump is seeking to protect these “good Americans” in a fashion familiar to Europeans: by threatening to withdraw normal legal and constitutional protections for those seen as “traitorous others.” For European far-right nationalists like those in Hungary’s Jobbik, the British National Party or the Party for Freedom in the Netherlands, this class usually includes some combination of Jews, Roma (also known as Gypsies), Muslim immigrants or foreigners from countries they dislike. For Trump, it’s Mexicans, Muslim-Americans, the journalists in the press pen or the black protester at his rally who maybe should be beaten up; he’s promised, in one such instance, to pay the legal bills of someone who tried to do just that.

Some will say Trump doesn’t believe any of this, and maybe he doesn’t. The point is that there’s a pretty big bloc of voters who are willing to endorse these views, and the moderate Republican Bob Doles and Susan Collinses of the world are willing to endorse a man who professes them. Far-right nationalism has, for the first time in at least a century, reached the presidential finals.

By any conventional analysis, Trump can’t win the general election, I told the European audiences. Polling and demographic data argue for an Electoral College landslide for Hillary Clinton in November, and a possible capture of at least one house of Congress. (Trump had won less than 40 percent of Republican primary votes at the end of last month, before his rivals dropped out.) But, I cautioned, by conventional analysis, Trump couldn’t have ended up poised to secure the Republican nomination either, so there’s that.

Trump’s foreign policy is anyone’s guess, in large part because the candidate appears to know very little about the outside world and is his own chief foreign policy adviser. Americans aren’t focused on foreign policy issues in this election, save for ones that affect them directly, like illegal immigration across the Mexican border, the threat of a terrorist attack or possible free trade deals. As for the policy choices in the Western Balkans, I told Serbs, few Americans know or care where that is on the map.

But our system grants a great deal of power to a president in their role as commander in chief, including control over a nuclear arsenal capable of destroying life on Earth. On the campaign trail, Trump has shown himself to be impulsive, thin-skinned and eager to respond to criticism with insult.

How would that play out in brinkmanship with North Korea’s Kim Jong Un, always eager to use insults, artillery fire or missile tests to try to provoke his adversaries? Let’s hope it’s all just another act, I suggested, just in case there really is a President Trump in the White House this time next year.