Donald Trump isn't like any politician America has seen lately. But European politics experts argue that his rise was eerily presaged by the assassinated Dutch demagogue Pim Fortuyn.

At first blush, Fortuyn may seem an odd choice as a Trump ancestor: Fortuyn was a gay sociology professor, about as far from Trump in background as you can imagine.

But both Fortuyn and Trump rose to prominence out of nowhere, almost exclusively by emphasizing anti-immigrant sentiment. Both men bucked the existing political establishment, and both proposed banning Muslims from entering the country.

Scholars of European politics argue that Fortuyn's rise shows Trump isn't a one-off phenomenon. Two non-politicians, in two very different countries, were capable of rising from nowhere with no real political organization or party backing them.

The issue that Fortuyn and Trump have raised — fear of the immigrant Other, in one form or another — appears to be orders of magnitude more powerful than your standard political controversy. And while Fortuyn's party collapsed in chaos after his assassination, Trump may actually be able to have a more lasting impact, if he's interested in building the institutions necessary to do it.

"Fortuyn gave [anti-immigrant sentiment] a voice, where the rest of the elite went back to a more politically correct discourse," Cas Mudde, a professor at the University of Georgia on the European far right, says.

Sound familiar?

The Fortuyn-Trump parallels are striking

The main differences between Trump and modern European right-wingers are about organization and ideology. European populists tend to be backed by political parties and extensive organizations, all united around a coherent worldview.

It has been fashionable, for instance, to compare Trump to France's Marine Le Pen, a charismatic leader whose popularity has grown recently. But Le Pen is backed by an entire party, the Front National, which has existed since 1972. That's about as far from Trump, an insurgent inside a party hostile to his candidacy, as one can get. Trump is nearly alone in coming from a realm outside politics, without any meaningful organization or ideology, and building a right-wing reactionary movement on the fly.

But Pim Fortuyn did it, too.

Fortuyn began his career as in the academy with a decidedly different ideology: a fairly hard-line socialism. But in 1988 he quit the academy, his Marxist struggle a thing of the past. He set up shop as a columnist at a Dutch center-right magazine and as a freelance political adviser, though he never became especially prominent.

His most famous work from this period was a 1997 book, Against the Islamization of our Culture. The basic argument in the book — that Muslim immigration was a threat to cherished Dutch cultural values, including women's equality and LGBTQ rights — would eventually form the foundation of Fortuyn's brief political career.

When he declared his candidacy in an August 2001 television appearance, not many people in the Netherlands knew who he was. But that changed, quickly. Like Trump, Fortuyn had the kind of bravado that TV cameras and headline writers everywhere love. He was ostentatious: Among other things, he employed a personal driver/butler, a rare extravagance in the humble, Calvinist Netherlands.

"From the moment he announced his participation in the elections, Fortuyn was in the media almost every day," Philip van Praag, a political scientist at the University of Amsterdam, wrote in a piece about the 2002 election.

Fortuyn, like Trump, initially didn't have much of a broader ideology. But he did know one thing: Muslim immigration was a threat to Dutch values. This "big idea" quickly came to define his campaign, helped along by the fallout from the 9/11 attacks.

"Early in his career, he made a couple of statements about Muslims — and from that moment on, that was the only issue, as with Trump," Mudde says. "Fortuyn never really fought against being positioned as an Islamophobe, because that was the basis of his support."

The result was something very much like the Trump phenomenon: a media frenzy that catapulted a charismatic political novice with no organization to the top levels of national politics.

"Very charismatic figure, appeared from nowhere, said we're full up and can't take any more [immigrants]," Tony Mughan, a professor at Ohio State University who studies European parties, says. "If you talk about someone who sort of comes from nowhere, Fortuyn is about as close [to Trump] as you'll get."

At times during his ascent, Fortuyn even talked like Trump. "It's just terrible," Fortuyn said of Muslim nations in a famous interview with the Dutch newspaper Volksrant. "All the hypocrisy:"

I don't hate Islam. I consider it a backwards culture. I have travelled much in the world. And wherever Islam rules, it's just terrible. All the hypocrisy. It's a bit like those old Reformed Protestants. The Reformed lie all the time.

These statements, and others, shocked polite Dutch society, which got Fortuyn plenty more media coverage — and built him a massive movement. In 2002, Fortuyn's Livable Rotterdam party won the city's municipal elections, unseating the Dutch Labour Party for the first time since World War II.

"He was perceived as incredibly threatening," Mudde says. "People said he was the new Hitler. That's the worst thing you can say in Dutch politics."

The deeper lesson: Immigration is a uniquely powerful issue for the far right around the developed world

Trump and Fortuyn, through either surprising insight or trial and error, picked up on an issue that mainstream politicians were ignoring but that much of the electorate cared deeply about. By bringing it to the fore, they built a wave of political support totally out of proportion to their actual organizational strength.

There appears to be a base for this kind of appeal in virtually every Western country. Right-wing populists across Europe, from France's Front National to Austria's Freedom Party, draw from the same core demographic group.

"In Europe, you have in principle a similar audience to the one that seems to be attracted to Trump," Herbert Kitschelt, a professor at Duke University, says. "It's essentially white, slightly overrepresented male, of lesser education."

Despite wildly different welfare states and immigration policies in the US and various European countries, the same group of people consistently feel like they're being failed — and are attracted to anti-immigrant demagogues as a result.

No other issue has this kind of power, across borders, to draw people to the revanchist right. Elisabeth Ivarsflaten, a comparative politics professor at the University of Bergen, compared seven different European countries with far-right parties in a 2008 paper. Specifically, she was looking to see what drove people to the populist right: dissatisfaction with the economy, distrust in political institutions, or anti-immigrant sentiment.

Her findings were unambiguous. "Immigration policy preferences are close to a perfect predictor of not voting for the populist right," Iversflaten found. By contrast, voters with right-wing economic views were barely more likely to vote for the populist right than an ordinary voter. Ditto those who didn't trust politicians very much, as the below charts make clear:

"This study therefore to a large extent settles the debate about which grievances unite all populist right parties," Ivarsflaten concluded. "The answer is the grievances arising from Europe’s ongoing immigration crisis."

Trump's rise, then, draws on a powerful political force that's been roiling European politics for decades. The sources of his appeal cannot be wished away by blaming Trump's rise on his celebrity.

The key test for Trumpism: institutions

No parallel is exact. Trump is operating in the context of the American conservative movement, which is of course quite different from anything in the Netherlands. Fortyun was also murdered by a far-left activist before he had a chance to contest a national election.

"To say that Fortuyn is similar to Trump is, in my view, a bit superficial," Kitschelt says. "To know what Fortuyn would have become would have required giving him a longer lease on life."

But in some ways, that's why the comparison works. Trumpism is still in its infancy as a political movement, much as Fortuyn's party was at the time of his death. The interesting question isn't so much who these sorts of charismatic leaders are when they start out, but rather how they change in order to build a durable support base.

"At the beginning of any party, you have some wide-eyed and wild-eyed policy entrepreneurs," Kitschelt explains. "Only the ones that resonate with the demand side of society can establish themselves. Whether and how Fortuyn would have achieved that, we'll never find out."

Whether Trump can do this — go from Trump the person to Trumpism the movement — is the key thing to watch for going forward. The most successful European right-wingers have all either taken over an old party or built up a new one. They found what society was demanding, as Kitschelt would put it, and created an institution that gave it to them.

Unless Trump actually wins the presidency, this is the only way his candidacy could be anything but a novelty in 20 years. He'll need a more cogent ideology, as well as people willing to dedicate their professional lives to implementing it.

It's not obvious that he's building that kind of philosophy or infrastructure. It's not obvious that he's interested in building that kind of philosophy or infrastructure.

But if Trump puts his mind to it, and actually attempts to create something out of the anger wave he's riding, things could end differently. The Trump campaign, ridiculous and incoherent as it seems right now, could be the beginning of something genuinely new: an American right-wing populist movement that draws on the same discontent that's currently roiling Europe.

Pim Fortuyn is dead. But what he represented may very well live on.