Many Americans are clinging to the idea that if Joe Biden wins the presidential election, calm can return to a nation riven by protests and rattled by President Donald Trump’s authoritarian rhetoric.

Not so fast, caution two academics who claim they have devised a measure of political instability that shows that the nation will still be a powder keg that is waiting to blow, even if a Biden landslide means that Trump has little choice but to step aside.

“The tendency is to blame Trump, but I don’t really agree with that,” Peter Turchin, an evolutionary anthropologist at the University of Connecticut who studies the forces that drive political instability, told BuzzFeed News. “Trump is really not the deep structural cause.”

The most dangerous element in the mix, argue Turchin and George Mason University sociologist Jack Goldstone, is the corrosive effect of inequality on society. They believe they have a model that explains how inequality escalates and leads to political instability: Worsened by elites who monopolize economic gains, narrow the path to social mobility, and resist taxation, inequality ends up undermining state institutions while fomenting distrust and resentment.

Building on Goldstone’s work showing that revolutions tend to follow periods of population growth and urbanization, Turchin has developed a statistic called the political stress indicator, or PSI. It incorporates measures of wage stagnation, national debt, competition between elites, distrust in government, urbanization, and the age structure of the population.

Turchin raised warning signs of a coming storm a decade ago, predicting that instability would peak in the years around 2020. “In the United States, we have stagnating or declining real wages, a growing gap between rich and poor, overproduction of young graduates with advanced degrees, and exploding public debt,” he wrote, in a letter to the journal Nature. “Historically, such developments have served as leading indicators of looming political instability.”

Today, with the nation in turmoil, Turchin’s prediction seems remarkably prescient. We live in a pandemic hellscape that has disproportionately harmed Black and brown Americans and those living in poverty. We have widespread civil unrest over racial injustice. And we are hurtling toward an election in which Trump is stoking unfounded fears of voter fraud and refusing to commit to a peaceful transition of power.

In August, Turchin gave himself a pat on the back for his predictive ability with an analysis showing a significant rise in political demonstrations and violent riots over the last 10 years. But he and Goldstone fear that much worse is to come.

The political stress indicator for the US is rising rapidly, much like it did before the Civil War.

When Goldstone talks about America’s darkest days in the 1860s, he provocatively calls it the “First Civil War.” He fears that we may be on the way to a second one, with the 2020 election serving as a potential “fire-starter” event.

Goldstone has some credentials in predicting conflict. In 1994, shortly after the US military’s ill-fated efforts to support UN intervention in Somalia’s civil war, which led to the downing of two Black Hawk helicopters and the gruesome spectacle of a dead US soldier being dragged through the streets, Goldstone was tapped by the CIA to help lead the State Failure Task Force. This group of academic social scientists was asked to identify factors that predict when a nation is likely to spiral into chaos.

The task force’s initial report, published in 1995, identified three risk factors that seemed to predict whether a state would fail within the next two years in about two-thirds of cases: high infant mortality, low openness to international trade, and level of democracy. On the last measure, partial democracies were more vulnerable to collapse than fully democratic states or autocratic regimes.

Goldstone continued to work on the project, later renamed the Political Instability Task Force, until 2012, tweaking its statistical model to predict both civil wars and democratic collapses with about 80% accuracy over the same two-year lead time.

He didn’t think of applying a similar approach to assess the risk of political conflict in the US until Turchin got in touch in 2015. “I didn’t expect political violence because I believed the US was a strong and flexible democracy,” Goldstone said.

But he is now convinced that Turchin’s PSI heralds a disturbing future for the US that won’t be solved by politics as usual after the 2020 election, even if Trump is defeated and goes quietly. “If those trends continue after Trump departs, then the risks and the occurrence of violence will likely continue,” Goldstone told BuzzFeed News.

“I’m worried about that no matter who wins,” he added. “The social problems are the gasoline. Trump is throwing matches.”

The PSI doesn’t explicitly address America’s deep divisions over racial justice. “Race has been an enduring faultline, ever since the founding of the Republic,” Turchin said. But he argued that it’s the additional dynamics captured by the PSI that explain why tensions are boiling over right now.

One key concern, according to Goldstone, is that people across the political spectrum have lost faith in government and political institutions. “In short, given the accumulated grievances, anger and distrust fanned for the last two decades, almost any election scenario this fall is likely to lead to popular protests on a scale we have not seen this century,” he and Turchin wrote in a recent article published by the Berggruen Institute, a think tank based in Los Angeles. This would hurtle the US into a period of political instability the researchers dubbed “the turbulent twenties.”

“Given the Black Lives Matter protests and cascading clashes between competing armed factions in cities across the United States, from Portland, Oregon, to Kenosha, Wisconsin, we are already well on our way there,” the article said. “But worse likely lies ahead.”

Turchin said people who rule out the possibility of serious political violence in the US based on “the strength of American institutions” are being “unduly optimistic.”

“The social system that we live in is extremely fragile,” Turchin said.

Other social scientists consulted by BuzzFeed News were skeptical that the US is on the brink of a civil war. But they were concerned about the trends highlighted by Goldstone and Turchin, and worried about the potential for violence around the coming election — especially from right-wing militia groups if Trump loses and contests the result.

“No matter what the outcome is, it is going to be disputed by some components of the other side,” Craig Jenkins, a sociologist at Ohio State University who studies political violence, told BuzzFeed News. “The difference is that the Trump forces have militia that have some capacity for violence and mayhem.”

One reason that most experts in conflict studies don’t predict an outright civil war as a consequence of the US’s gap between rich and poor is that inequality hasn’t emerged as a major driving factor in studies of such conflicts in the modern era.

“Civil war has been predominantly a phenomenon in low-income countries,” James Fearon, a political scientist at Stanford University and coauthor of a 2003 paper that identified national poverty as an important condition that can lead to violent insurgency, told BuzzFeed News.

Another influential study, published in 2000 by the economists Paul Collier of the University of Oxford and Anke Hoeffler, now at the University of Konstanz in Germany, suggested that an armed group’s ability to seize control over significant economic resources - such as diamonds in several conflict-prone African nations and drug crops in Colombia - was a key driver of modern civil wars.

As a rich nation with a diverse and robust economy, the US should have a fairly low chance of falling into civil war according to these theories. And if push comes to shove and order needs to be restored by force, few experts in political conflict expect even a well-armed militia to be a match for federal law enforcement or the National Guard.

The circumstances in the 19th century that led the US into the bloodiest conflict in its history were also unusual. The young nation was growing, adding states that either opposed or supported slavery, creating a fundamental economic and moral divide that couldn’t easily be resolved. “That was an irreconcilable dynamic,” Jenkins said. “I think you need the accumulation of irresolvable conflicts to get a true civil war.”

But recent events, notably the plot by a group of right-wing militants to kidnap and potentially kill the Democratic governor of Michigan, Gretchen Whitmer, over her policies to limit the spread of the coronavirus, have shocked even skeptics of the idea that the US is teetering on the brink of civil conflict. “This is really concerning,” Fearon said.

The PSI isn’t the only indicator that has set alarm bells ringing about the stability of the US. The Fund for Peace, a nonprofit based in Washington, DC, has developed a measure called the Fragile States Index (FSI) that, like the work of the State Failure Task Force, seeks to identify nations that are at risk of violence and instability from a range of underlying pressures including economic distress, refugee flows, and their record on human rights.

Overall, the US looks reasonably healthy on the FSI, ranked 149th out of 178 countries for its potential for instability. But there are worrying signs for the US on a component of the FSI labeled “cohesion,” according to Fund for Peace programs manager Natalie Fiertz. “Over the past decade-plus, we’ve seen very rapid worsening of the score for those dimensions,” she told BuzzFeed News.

The Fragile States Index shows that the US is becoming a less cohesive society.

This chart shows change in the average score across the three cohesion components of the FSI for the members of the G7 group of rich democracies. These measure security threats including terrorism and organized crime, factionalization of a nation’s elites, and schisms between different groups in society.

Not surprisingly, given the intense and growing political polarization in the US, it is the last two measures that explain why the nation’s cohesion score has gone from the second best among the G7 to the worst in just 15 years. (In recent years, the UK has closely followed the US on this measure, driven by its own political divisions over Brexit.)

But political polarization may be just another consequence of the economic inequality that Goldstone and Turchin argue lies at the heart of the US’s current vulnerability to political violence.

Political scientists have put a great deal of energy into identifying why polarization in the US is escalating. But factors including the influence of partisan cable TV news and congressional redistricting don’t seem to provide the answer - the latter, for instance, can’t explain why the Senate has become increasingly divided.

What is clear is that polarization in Congress has historically tracked closely with income inequality. And recent studies have shown that states with greater income inequality tend to have more polarized state legislatures - supporting the idea that inequality is a fundamental cause of America’s deep political divisions.

Even the International Monetary Fund has weighed in, warning nations of the corrosive effects of inequality in a 2017 publication: “While some inequality is inevitable in a market-based economic system, excessive inequality can erode social cohesion, lead to political polarization, and ultimately lower economic growth.”

Inequality can also damage public health. In their 2009 book The Spirit Level, the British epidemiologists Kate Pickett of the University of York and Richard Wilkinson of the University of Nottingham looked at differences across rich nations for an index of health and social outcomes including infant mortality, life expectancy, mental illness, incarceration, and literacy. They could find no correlation with gross national income per person, but found a strong relationship between poor outcomes and inequality, measured by the gap in incomes between the top and bottom 20% of a country’s earners.

“Inequality is a social stressor,” Wilkinson told BuzzFeed News. “One of the big changes in our understanding of social determinants of health is the role of chronic stress.”

The pandemic has made inequality much worse - but it may also be a catalyst for change.

Given all of the evidence linking inequality to a raft of bad outcomes, it should come as no surprise that unrest has surged during the coronavirus pandemic. Americans living in poverty and people of color have not only been disproportionately sickened and killed by the virus, but they have also been hit harder by the recession it has caused - which has further widened the gulf between rich and poor.

“What we need is a new social contract that will enable us to get past extreme polarization to find consensus, tip the shares of economic growth back toward workers and improve government funding for public health, education and infrastructure,” Goldstone and Turchin wrote in their Berggruen Institute article.

Can that really happen in today’s combat zone of weaponized social media, in which even modest proposals to ratchet back inequality are framed as “communism”?

One hopeful sign is that the US has pulled back from the brink of chaos before through similar reforms, within the lifetime of its oldest citizens. In the 1930s, as parts of Europe slid into fascism, the US went in a different direction, electing Franklin D. Roosevelt to drag the nation out of the Great Depression by ushering in the New Deal.

At least some social scientists think the US could pull off a similar feat again. “You can reform your way out of dramatically polarized societies,” said George Lawson of the Australian National University in Canberra, who has studied societal transformations including the peaceful transition to majority rule in South Africa.

Even given Trump’s flouting of democratic norms and the current upsurge in civil unrest, Lawson believes the US, by and large, has withstood a political “stress test.”

“I would err on the side that the system has shown to be more robust than fragile,” Lawson said. “One thing to come out of the past few years is an energization of political engagement that is healthy.”