Donald Trump poses for a photo after an interview with Reuters in New York City, May 17, 2016 Lucas Jackson/Reuters

Pundits and academics have been struggling for months to understand the rise of Donald Trump. Some have argued the presumptive Republican nominee draws his power from authoritarian voters, while others say he has successfully capitalized on white resentment. These theories are not necessarily mutually exclusive, and some have considerable overlap. But they only indirectly address the much larger factor that could explain Trump’s ascent.

What if the inevitability of death is the key to understanding 2016?

For thousands of years, philosophers and theologians have tried to grasp what it means to live in the shadow of death. More recently, psychologists have taken up the challenge as well. Academics working in the burgeoning field of Terror Management Theory have spent the past three decades studying how our knowledge of death’s inevitability shapes every aspect of human life — including our politics.

One of Terror Management Theory’s pioneers, Skidmore College professor Sheldon Solomon, has spent his career studying the relationship between people’s behavior and their awareness of their own mortality. In 2015, he decided to examine the particular effect mortality awareness had on support for Trump. The New York billionaire had recently launched his campaign for the Republican nomination but was still far from becoming the presumptive nominee.

The results of Solomon’s study were unambiguous. People who were reminded of their own death were far more likely to support Trump.

To reach that conclusion, Solomon randomly sorted 152 college students into two groups. The first group was prompted to answer the following question: “Please briefly describe the emotions that the thought of your own death arouses in you.” That was followed with another prompt: “Jot down, as specifically as you can, what you think will happen to you as you physically die and once you are physically dead.” The other group was asked questions about pain, but not death.

After completing these questions, both groups were asked questions regarding Trump’s leadership, and positive attributes. Support for Trump was far higher among people who had been asked to consider their own mortality — no matter their political orientation.

Solomon told International Business Times the results of that initial experiment line up with what previous studies have shown. When people are forced to confront mortality, they are likelier to embrace charismatic nationalists.

“This has ominous implications for democracy,” Solomon said.

How ominous? The answer to that question can be found in the work of Ernest Becker, the grandfather of Terror Management Theory. Becker was largely disregarded by his colleagues throughout his career, and he did not live to see the publication of his most significant work, “The Denial of Death,” in 1973. But a few years later it caught the eye of Solomon and two of his fellow psychology majors at the University of Kansas, Jeff Greenberg and Tom Pyszczynski.

Together, Greenberg, Pyszczynski and Solomon have spent much of the last 30 years corroborating Becker’s theories with experimental data. Although Becker was ignored and marginalized in his own time, their work has given him renewed prominence. Their 2015 book “The Worm at the Core: On the Role of Death in Life” synthesizes decades of empirical research into Becker’s central claim that humans spend most of their lives struggling to transcend mortality.

Terror Management Theory says people do this in two ways. On the one hand, some try to achieve literal immortality through things like prayer, religious ritual and cryogenic freezing. On the other hand, nearly everyone aims to achieve symbolic immortality through fame, lasting accomplishments or progeny who will carry on their name. People can also achieve a measure of symbolic immortality by dedicating themselves to a grand cause, such as a political movement.

Becoming a part of something greater than one’s self can be perfectly benign or even noble. But it also has a dark side. In times of political instability or economic distress, people are drawn to charismatic nationalists who offer them protection and vicarious immortality.

“Teeming with admiration and sensing a way to feel significant again, people join the cause of the seemingly larger-than-life leader as a revitalized basis of self-worth and meaning in life,” write Greenberg, Pyszczynski and Solomon in “The Worm at the Core.” “Nationalism and passionate affection for, deference toward and identification with charismatic leaders therefore supplies what [Austrian psychoanalyst Otto Rank] aptly dubbed ‘collective immortality’ to satisfy our aching need for heroic triumph over death.”

The authors cite Adolf Hitler as one such giver of collective immortality. Nazism, they note, came to power in Germany while the country was weathering a severe economic depression. Adding to the ideology’s appeal, Hitler vowed he would cleanse Germany of the humiliation caused by the punitive Versailles Treaty that followed World War I’s end.

Nazis also “seemed to have a pathological affection for death,” according to “The Worm at the Core.”

Donald Trump is not Adolf Hitler, as Solomon was careful to stress in his interview with IBT. Many scholars of fascism have classified Trump as a modern right-wing populist, not an outright fascist. But Solomon pointed out the Republican nominee’s rise has been facilitated by global instability, fear of terrorism and illegal immigration, and the lingering effects of the Great Recession.

“When Trump declared that he was going to run for president, and he declared that he was going to do so under the guise of making America great again, literally the first thing out of his mouth was that Mexicans are rapists so we’ve got build that big wall,” said Solomon, referring to one of the more incendiary claims from Trump’s announcement speech. “And then he implied that most adherents to Islam are terrorists, so we’ve got to keep them out.”

According to Terror Management Theory, fear of death can help strengthen cultural prejudices as people flee deeper into the belief networks that promise them symbolic immortality. Solomon has done research suggesting that Americans experience unconscious thoughts of death more frequently after being asked to contemplate what would happen if undocumented immigrants moved into their neighborhood, or if a mosque were built nearby.

“We’ve got a pretty vicious, not so virtuous cycle here, because just the mention of either immigrants or Muslims is sufficient to make death thoughts salient,” Solomon said. “And that, in turn, increases support for charismatic leaders.”

He found similar results when studying support for President George W. Bush approximately 10 years ago. Along with Greenberg and Pyszczynski, he ran tests that seemed to indicate the Sept. 11 terror attacks reminded Americans of their own mortality and drove them to identify Bush as the sort of charismatic figure who could extinguish those thoughts.

Trump may be an even more potent identification figure than Bush because he has something the former president lacked: a popular reality TV show. Long before he was a political figure, Trump was a celebrity, known for his ostentatious displays of wealth. Both wealth and celebrity also convey a glimmer of vicarious immortality, according to Terror Management Theory.

“Trump is bigger than life. He’s had a TV show, he has Trump Tower in New York,” said Greenberg, who teaches at the University of Arizona. “He’s a guy who will leave a legacy. He already seems like an eternal figure who will outlive his existence. In a sense, we all want that. So if we can’t be Trump, we can try to feel connected to him.”

Trump’s appeal as a death-denying figure does have limits. While the Republican Party is consolidating around him, polls show he is still struggling to make inroads with the rest of the electorate.

Now that Trump is the presumptive Republican nominee and Hillary Clinton has almost locked down the Democratic nomination, Solomon plans to run more tests related to the election. But he said it’s possible that the threat of a Trump presidency could make fearful liberals more, not less, conscious of their own mortality.

“At least in our studies of 2004, death reminders made all Americans, regardless of political affiliation, support President Bush more than [Democratic challenger John] Kerry. But it is not inconceivable that it could go both ways this year,” he said.

If that turns out to be the case, then humankind’s terror of mortality could work against Donald Trump just as much as it works for him.