Never have so many risked so much for so little.

I'm talking, of course, about Britain's upcoming vote on whether to leave the European Union. So-called "Brexit" — get it, as in British exit? — would be the economic equivalent of quitting your job because you think you can get it back minus all the parts you don't like. In other words, a fantasy. But, with apologies to Harry Potter, it might be Britain's most popular one to the point that there's a real, albeit slight, chance it could prevail in the June 23 poll. In which case, to extend this metaphor, Britain would be left out of work and out of friends. Indeed, Britain's Treasury estimates it could send them into a recession costing as many as 500,000 to 800,000 jobs.

What in the name of rational self-maximizers is going on? The same thing that's happening everywhere else. Right-wing populists are trying to make their country great again by, you guessed it, keeping immigrants out and negotiating great, and I mean great, deals. In Britain's case, the U.K. Independence Party (UKIP) wants to leave the 28-nation free trade zone that is the EU in hopes of coming to terms on a new free trade pact with the now-27-nation EU that wouldn't require them to follow Brussels' diktats on, say, how strong vacuum cleaners are allowed to be, or, more saliently, how many immigrants they have to accept from the rest of Europe.

It almost sounds reasonable. Until, that is, you actually think about it. UKIP is asking for all of the benefits of EU membership without any of what it thinks are the costs. Which, of course, everybody would want if it was possible. The problem there, though, is an EU that exists on an à la carte basis today is an EU that wouldn't exist at all tomorrow. So Brussels would never go along with this. It would tell Britain that it has to unreservedly play by Europe's rules—at least the most important ones—if it wants unreserved access to Europe's market. That, after all, is what Norway has had to do to get a free trade deal with the EU without being a part of it. Practically speaking, that would mean continuing to pay into the EU budget, adhering to big EU regulations and, yes, allowing the free movement of people within the EU. The best-case scenario, then, is that Brexit would "only" result in a few years of economy-killing uncertainty while they negotiated a deal almost identical to the one they had just ripped up. And the worst is that they would be unable to reach any kind of agreement, leaving themselves permanently poorer.

But despite all this, almost half the country thinks this is a good idea. Surprised? You shouldn't be. This is what happens during a depression. Now, I know it sounds strange to invoke the sepia-toned suffering of the 1930s when we're talking about an economy that only has 5.1 percent unemployment right now, but you have to look at the past eight years and not just the past eight months. By that measure, Britain is doing worse than it was at this point of the Great Depression or even its post-World War I slump. The tricky thing, though, is this hasn't been due to the downturn being deeper this time around, but rather to the upswing not being much of one. But in any case, it's added up to Britain's gross domestic product per capita growing three to four times slower than it did during these other economic catastrophes.

The other part of this is that, as de Tocqueville told us, there's nothing more dangerous than unmet expectations. That, at least, is what economists Alan de Bromhead, Barry Eichengreen and Kevin O'Rourke found when they tried to figure out what explained the rise of right-wing extremism in the 1930s. "What mattered," they wrote, "was not the current growth of the economy but cumulative growth." Which is just another way of saying that it wasn't a question of how fast you were moving toward where you thought you'd be, but rather how far you were from it.

That's why it's no surprise that right-wing populism is on the march in Britain and everywhere else for that matter. People are poorer than they thought they'd be, so they don't feel like they can afford to be as generous to immigrants anymore. That's even true in the erstwhile socialist utopias of Denmark, Sweden and Finland, where the right-wing Danish People's Party, Sweden Democrats (who have their roots in neo-Nazism), and Finns Party have all risen near the top of the polls. What else did you think was going to happen when, as you can see below, your economy is doing worse than it did during the Great Depression?

A 1930s-style economy creates 1930s-style politics.

But before you move to Canada, there is some good news. Today's right-wing populists, depending on your opinion of Donald Trump, aren't fascists so much as nationalists. So they might exploit racial tensions and they might be illiberal, but they probably don't want to start World War III. The not-so-good news, though, is that it's going to take a lot more than economic growth to make them go away. Sure, good times should be bad ones for them — at least enough to knock them off the top of the polls — but probably not so much that they become irrelevant. Remember, far-right politicians like America's Pat Buchanan, France's Jean-Marie Le Pen and Austria's Jörg Haider were all able to score surprising victories during the relative boom times of the late 1990s and early 2000s. That's because immigration and globalization are both social issues as much as economic ones that have been fertile ground for nationalists regardless of the state of GDP growth.

What we're saying, then, is that there's been a baseline of right-wing populism the past 25 years as immigration has reshaped countries' identities and deindustrialization has reshaped their economies. And that it's spiked as economic growth has flatlined since 2008. The result is right-wing populist parties are, if not getting closer to power, at least setting the terms of the debate in the U.S., U.K., France, Germany, Austria, Denmark, Sweden, Finland, Slovakia, and Croatia, not to mention actually winning it in Hungary and Poland.

It turns out Marx didn't have it quite right. A specter is haunting the European Union — but it's the specter of nationalism.

On June 23, Britain faces a fateful decision: whether or not to leave the European Union. And the world will be watching. (Daron Taylor, Jason Aldag, Danielle Kunitz/The Washington Post)