Over the last few months, comedian Bill Maher has repeatedly rooted for an economic crash, seeing it as one sure method to defeat Donald Trump next year. “I feel like the bottom has to fall out at some point,” he said in June on his HBO show. “And by the way, I’m hoping for it. I think one [way] you get rid of Trump is a crashing economy.”

“So please, bring on the recession,” Maher added. “Sorry if that hurts people, but it’s either root for a recession or you lose your democracy.”

The sight of a multimillionaire like Maher gloating over the prospect of economic suffering isn’t an attractive one. It’s not surprising that right-wing outlets, notably Fox News, have highlighted Maher’s comments as a way of making liberals look bad. But, unseemly as they are, Maher’s remarks do carry a narrow ring of partisan political truth. It’s generally true that incumbents who preside over a downturn will be voted out.

Recent economic headlines suggest Maher may get his wish. Over the past week, market analysts have been spooked by a spate of bad news: the inversion in the bond market of the yield curve, a slowing of major economies like Germany and China, and continued rockiness in the stock market. As Politico notes, “An inversion in this corner of the bond market has occurred before every recession since the 1950s, raising the potential for the 2020 election to look more like 2008 when a cratering economy dominated the political debate. That could derail Trump’s plans to make 2020 more like 1984 when Ronald Reagan ran a ‘Morning in America’ campaign based on faster growth.”

Yet Democrats shouldn’t cheer on the recession—and not just for moral reasons. While bad economic times, if they come, will help defeat Trump and the GOP in 2020, they’ll also sow the seeds for an even more reactionary politics in the future. If history is any guide, an economic slowdown will make the American people more racist and less open to progressive policies, a likelihood increased by the fact that the current Trumpian moment is already a product of the Great Recession of 2008, the scars of which are still felt by many ordinary people.

There’s a school of progressive thought that resists the idea that economic anxiety produces racism. This formula seems like an excuse for bigotry. But if we refine the argument in a way that doesn’t exculpate prejudice, it points to an undeniable truth: While economic anxiety doesn’t produce racism, racists often exploit economic anxiety as a way of scapegoating minorities and advancing their agenda.

In his 2005 book The Moral Consequences of Economic Growth, Harvard economist Benjamin Friedman argued that that robust economies generally result in nations that are tolerant and outward looking, while prolonged economic turmoil makes people more narrow-minded, bigoted and selfish.

“The consequences of the stagnation that lasted from the mid-1970s until the mid-1990s was, in numerous dimensions, a fraying of America’s social fabric,” Friedman contends. “It was no coincidence that during this period popular antipathy to immigrants resurfaced to an extent not known in the United States since before World War II, and in some respects not since the 1880s when intense nativism spread in response to huge immigration at a time of protracted economic distress.”

If the unemployment rate spikes up again, Democrats could have a field day talking about Trump’s recession. But Trump won’t take it lying down. With his shrewd feel for nativist grievances, he’ll realize that many of his supporters will blame bad times on people of color, especially immigrants. Even if Trump is voted out of office, the GOP is likely to radicalize further along the trajectory that took them from Sarah Palin to the Tea Party to Trump.

If there is an imminent recession, Democrats need to see it as not just an electoral opportunity but also as a political problem. How are they going to keep the public receptive to transformative policies, when recessions typically make voters more skittish and less generous?

Friedman’s history offers a clue, since there is one major downturn that defies to the rule. “The 1930s stand out as an exception—in many respects, the exception—to the more general tendency in the American experience for economic stagnation or decline to erode the society’s tolerance, openness, and democracy,” Friedman observes. “Instead, America during the Great Depression strengthened its commitment to these positive values and, moreover, did so in ways that proved lasting.”

The New Deal was far from perfect. Franklin Roosevelt’s compromise with racist white Southern Democrats was a moral stain. But he also helped make the Democratic Party a beacon of pluralism, appointing Jews and Catholics to prominent positions. In the North, the New Deal coalition also included African Americans, who helped push the Democrats toward reviving the civil rights agenda that had languished since Reconstruction was terminated.

Friedman doesn’t offer any very convincing explanation as to why the New Deal was so exceptional, although certainly circumstantial reasons helped. The fact that Herbert Hoover presided over the economic collapse for two years helped discredit Republicans (by contrast, George W. Bush oversaw only a few months of the beginning of the economic wreck he created).

But, besides good luck, Franklin Roosevelt had the right instincts. He resisted any temptation to create a centrist consensus during a national emergency. Instead, he forthrightly referred to his opponents as economic royalists who ruined the nation. FDR wasn’t afraid to play class politics. Roosevelt was helped by the fact that robust social movements, particularly labor unions, held his feet to the fire and kept pushing him left.

The New Deal example shows that an economic downturn doesn’t have to mean a more reactionary politics. But to avoid a shift to the right, the Democrats have to be as bold as Roosevelt. If there is a recession they have to pin the blame squarely on Trump—and create a lasting narrative of how his xenophobia and reckless policies squandered Obama’s legacy. They have to offer a robust alternative to the status quo. And they have to uphold the values of pluralism even as nativist and racist voices grow louder.

The coming of a recession makes the case for an Elizabeth Warren or a Bernie Sanders all the more urgent.

Democrats can’t just hope that a recession will save them. They have to prepare for the recession and figure out how it can be used to promote progressive ideas, rather than another reactionary backlash.