There have been many attempts to explain the rise of Donald Trump, focusing on economic frustration, racial resentment or a combination of the two. Now, as we transition from the primary season into the general election, there’s the added question of what his political legacy will be, both to the GOP and the nation in general. Will his nativist and anti-immigrant brand of populism become a historical footnote, or will it find a root in our two-party system?

Although there are many differences between political systems in Europe and those in the U.S., the rise of far-right parties in Europe provides perspective on the issues that drive nativism and its political staying power. Europe’s far-right parties often focus on restoring a national culture that predates the influence of immigrants (and sometimes of global multinational corporations); the preservation of jobs for native-born citizens who are part of majority cultures; and, at their most extreme, embrace notions of racial superiority and even neo-Nazism.

Different versions of the same broad issues are affecting politics both in the U.S. and in Europe, namely dissatisfaction with the economy and demographic change via immigration. The migrant crisis has been one prompt for the rise in nativist sentiment in Europe, with 1.3 million people from nations including Syria applying for asylum in the European Union in 2015 alone. Far-right parties — and even some more moderate politicians — criticize the resettlement of refugees as changing national character and bringing high financial costs.

Many of Europe’s far-right parties have been active since the 1970s, changing in level of support but weathering many economic cycles. Worth noting, however, is that these parties do experience a bump during and after economic downturns, according to a German study tracking far-right parties in more than 20 countries, in some cases with data from as far back as the 1870s.

Many of the 28 nations in the European Union have experienced an intense and painful set of downturns since 2009 (including bailouts in nations such as Greece), broadly described as the eurozone crisis. Today, the unemployment rate in the EU is 8.8 percent, but it varies widely from nation to nation; in January, Greece’s unemployment rate was 24 percent, while Denmark’s was 6 percent. Both these nations have their own far-right parties with sitting members of parliament: the often violent neo-Nazi Golden Dawn in Greece and the anti-immigrant, anti-EU Danish People’s Party, which won 21 percent of the vote in last year’s election.

The DPP is one of the most regionally powerful far-right parties in the European Union, but its success — and that of other such parties — cannot be attributed to economics alone. “It’s not just about jobs,” said Matthew Goodwin, a professor of political science and international relations at the University of Kent in the United Kingdom. “People are feeling their values, national culture and identity are under threat from rapid demographic change.” Not every far-right party is equally successful, but they are widespread and include the Lega Nord in Italy, the Swiss People’s Party, the neo-Nazi People’s Party — Our Slovakia, the English Defence League and the Alternative for Germany.

An in-depth multination analysis, published in 2011 by the German foundation Friedrich Ebert Stiftung, shows that these parties have grown in popularity over the past three decades. Yet in some cases, popularity does not translate into power. For example, France’s National Front won 27 percent of the popular vote in regional elections in 2015, its largest tally since the party was founded in 1972. That vote happened just a month after 130 people were killed by Muslim extremists in terrorist attacks in and around Paris. But a pact by other parties in a second round of voting prevented the National Front from winning control even in regions where it led the first round of ballots.

Although the national dynamics in the U.S. are different, the economy and immigration both stand out as drivers of Trump’s rise here. While the national unemployment rate is just 5 percent, that doesn’t reflect underemployment or discouraged workers who’ve stopped looking for jobs. Resentment at the state of the economy reflects measurable stagnation in real median household income, which was $55,565 in 2004 and $53,657 a decade later. But as my colleague Nate Silver has pointed out, the median income of Trump voters, as reported in exit polls, is still significantly higher than that of people who voted for either of the Democratic contenders. Similarly, although white Americans without a college education are disproportionately likely to support Trump, he has plenty of college-educated supporters as well.

Even though Trump’s ideology is conservative on many issues, his positions on trade protection and U.S. intervention in overseas conflicts can overlap with the left-populist positions of a candidate like Bernie Sanders. German political strategist Simon Vaut notes that far-right parties in Europe don’t fit with the American sense of the political right favoring free and globalized markets. “Most of the European far-right parties are National Socialist. France’s National Front, for example, has an anti-immigration platform but is also anti-free-market and wants a paternalistic welfare state,” he said in an email. He sees Trump as akin in style to former Italian Prime Minister Silvio Berlusconi, a self-congratulatory billionaire media tycoon who survived several scandals only to be convicted of tax fraud in 2013.

So, just as in Europe, economics and conservative ideology explain only part of the Trump phenomenon. Goodwin, for one, doesn’t believe economic cycles are the primary driver of affinity for Europe’s far-right parties or for Trump. “The core motives are concern over immigration and diversity, concern over perceived loss of values and ways of life,” he said. “They will not evaporate after the U.S. presidential election in November or the French election in 2017.”

Trump has hammered away at these themes: He wants to restrict Muslims from immigrating to or even entering the United States, and he wants to build a wall on the Mexican border. Although Muslims are only 1 percent of the U.S. population, a majority of Republican voters (and in some polls, of all Americans) now support Trump’s proposed ban on Muslim immigrants and visitors. While 59 percent of American voters oppose the border wall, 84 percent of Trump supporters favor the plan.

Cas Mudde, a political scientist at the University of Georgia, was raised in the Netherlands and has extensively studied far-right politics. He sees parallels in how both the American insurgent and the established European parties court their followers. “Both Trump and the European far right mobilize mostly on the basis of nativism, authoritarianism and populism — although Trump is more anti-establishment than pro-people, as he is mainly pro-Trump,” he said in an email.

Unlike his European counterparts, Trump is prone to ideological offroading versus staying on-message, for example publicly changing his stance on abortion several times. If he becomes the Republican nominee, as seems all but inevitable, it could throw the party platform into chaos where his beliefs differ from those of establishment Republicans. And unlike in Europe’s multiparty democracies, there is little room for factions to coexist easily within our political system, Mudde said. “The two-party system forces the radical right (and left) to mobilize with the mainstream right (and left).”

What does this mean for America’s long-term political future? “In the U.S., the sentiments will remain, but Trump will leave little legacy, as he has not created any institutional structure — either within the GOP or outside of it,” Mudde said. But he added, “If Trump wins, all bets are off!” The reluctance of the GOP establishment, from House Speaker Paul Ryan to the Bush family, to embrace Trump hints that his brand of nativist populism may not flourish in the post-Trump iteration of the GOP. But Goodwin argues that even if he loses, Trump’s candidacy could still reshape American politics: “The risk will come when many Republicans assume that this evaporates after November. Once radical right movements get established, they may ebb and flow like waves, but they only rarely disappear.”