Bernie Sanders looks increasingly likely to be the first self-declared socialist to head a major party in the history of the United States, especially after romping through Nevada on Saturday. The reasons for the socialist revival are clear. Inequalities are shocking, student debt levels are staggering, and living standards have been stagnant or declining for all but the 1 percent since the 1970s. Sanders’ brand of democratic socialism, which really differs little from New Deal liberalism, seeks to address these inequities.

But there also exists a latent, darker impulse that has persisted throughout American history: panic about socialism. Anti-socialist hysteria was not exclusive to the 1950s Cold War. It has recurred in various forms in the United States for more than 150 years.

If Sanders wins the Democratic nomination, his ascendancy, combined with extensive paranoia about immigration, Muslims, and the decline of the white majority, means America is due for another Red Scare. And what might this Red Scare look like?

There will likely be congressional hearings into left-wing organizations, individuals, and associations. Justice Department resources could be unleashed on anyone connected to Venezuela and other countries that call themselves socialist. And Trump, Republicans, and Fox News will target not just democratic socialists like Sanders, but liberals in general and the whole Democratic Party, who must unite to fight it.

Throughout our history, socialism has been branded as anti-American because collectivism conflicts with ingrained American notions of individual rights, self-reliance, republicanism, and anti-statism. Nonetheless, socialists and other radicals have made enormous contributions, notably in the Progressive Era, when their efforts were crucial to to the first serious successes in reforming capitalism, resulting in laws regulating monopolies and food and drug companies and establishing and improving environmental conservation, public education, and working conditions.

But alongside these achievements sprouted a terror of socialism that has periodically swept the country and reached the highest levels of state. The first Red Scare from 1917-1920 was unique in its scope, scale, and intensity. The hyper-nationalism and suppression of civil liberties accompanying World War I, combined with the Russian Revolution, homegrown strikes, and mail bombings, led Attorney General Mitchell Palmer to launch raids on leftists of all kinds, and Jewish and Italian immigrants. Thousands were arrested and deported.

Of course, the onset of the Cold War in the late 1940s inspired the best-remembered Red Scare. The interrogations of thousands of individuals and organizations by government officials, blacklists, imprisonment of leftists and televised hearings, all within living memory of millions, was a uniquely American response to Cold War pressures.

The Cold War ended in 1991, but even after it, we’ve seen the same impulse at work. Following decades of demographic shifts that gradually reduced the dominance of white people, Barack Obama’s presidency inspired a smaller-scale Red Scare. Although he was a mainstream liberal with a Harvard University degree and white Kansan mother, his part-African heritage was inevitably going to spark some sort of panic among conservatives.

When Obama tried in the wake of the housing collapse to help underwater homeowners—people Republicans tarred as irresponsible, lazy minorities— the panic took the form of the Tea Party, which initially claimed to be more angered about the president’s alleged socialism than his race or religion. Donald Trump’s targeting of Muslims, immigrants, and Mexicans clarified that what had animated the concerns about socialism were actually concerns about cultural change. The two have always mixed together in the American mind.

If Sanders becomes the nominee, Republicans will repeat the pattern that has recurred since the Civil War era: they will unleash another Red Scare. Comfortable as lawmakers have become with sham investigations into things like Benghazi and the IRS non-scandal, there will almost surely be congressional investigations into anyone and anything tarred as left-wing.

Although Sanders and other contemporary socialists are democratic and anti-authoritarian, they will be conflated with the horrors of Venezuelan’s government, just as American Muslims and Arabs are made to answer for the acts of jihadists. Individuals from Latin America could be deported, legally or otherwise. Immigration from countries south of the border could be halted. There could be Justice Department raids on the Democratic Socialists of America, the organization whose membership has mushroomed in the wake of Sanders’ rise since 2015.

“ If Sanders becomes the nominee, Republicans will repeat the pattern that has recurred since the Civil War era: they will unleash another Red Scare. ”

In the states, the socialists who have been elected to legislatures from New York to Seattle to Georgia in recent years are likely to be harassed. Also at the state and local levels, laws banning socialists or socialism will almost surely be passed in some states. Between voter suppression and gerrymandering, Republicans routinely defy majority opinion and the rule of law to maintain power—they will not hesitate to use anti-socialist hysteria to do the same thing now.

Importantly, the current socialist movement—and the Democratic Party as a whole—is broadly supportive of immigrants and racial justice. Previous labor movements, conversely, have sometimes been nativist and racist. Trump and Fox News will increase their racist attacks on the four congresswomen known collectively as “the Squad”—Reps. Ilhan Omar of Minnesota, Alexandria Ocasio-Cortez of New York, Rashida Tlaib of Michigan, and Ayanna Pressley of Massachusetts.

All are women of color, and all but Pressley have spoken favorably of socialism. Organizations like the Council for Islamic-America Relations could be designated as terrorist groups, with conservatives fabricating claims of associations with terrorists.

Since Sanders is Jewish, the new Red Scare will likely have an anti-Semitic component. Vandalism and assaults on individual Jews could surge, and Trump may well begin to question the loyalty of Jews and make more overt antisemitic statements than he has in the past. When they inevitably protest, groups like the Anti-Defamation League will come under attack from Republicans.

President Trump is unique among presidents in his overt bigotry, affection for authoritarianism and cruelty, social Darwinian worldview, and disdain for the rule of law and judicial independence. He is now the conductor of the Republican orchestra, directing his players to annihilate the Democratic Party by any means necessary. Any decent conservatives wishing to opt out of Trump’s whirlwind of noise are simply kicked out of the ensemble.

The contemporary Republican Party represents an ideologically and demographically homogeneous chunk of the country, determined to maintain its grip on power, even if it means using undemocratic methods. Their control of the presidency, the Senate, and the Supreme Court mean their potential to enact harm as part of their anti-socialist agenda is enormous. Even if Sanders defeats Trump and becomes president, Republicans will continue to wage war on socialism and liberalism.

Whatever they think of Sanders, all Democrats must join with leftists in opposing the new Red Scare. Anything but a united front will mean devastation to the party as a whole—Trump and his associates will not discriminate between socialists and traditional liberals and Democrats. More importantly, it will be incumbent upon moderates and liberals to join with leftists in protecting civil liberties and the rule of law.

Since the 1960s, a greater focus on preserving liberties has emerged. Stronger efforts and institutions exist to protect the vulnerable today than existed in the 1950s. Perhaps a stronger left will be better equipped to defend itself this time around.

Or perhaps Trump will unleash the powers of the federal government in ways that America is unable to withstand.

Either way, another Red Scare is coming.