Some of the biggest questions about President Trump involve his followers. Who are they, what do they want, and why do they support him no matter what? “Authoritarian Nightmare: Trump and His Followers,” co-authored by John W. Dean and Bob Altemeyer, is an effort to answer those questions. Without his supporters, “Donald Trump would be nothing but a Twitter troll,” they assert.

Dean has seen presidential malfeasance firsthand. He served as White House counsel for Richard Nixon, was involved in the Watergate coverup, later provided congressional testimony about Nixon’s culpability, became a key prosecution witness in the trials of Nixon administration officials and pleaded guilty to obstruction of justice.

He has also written “Blind Ambition: The White House Years” and “Lost Honor: The Rest of the Story”; “Worse Than Watergate: The Secret Presidency of George W. Bush”; and “Conservatives Without Conscience,” which used Altemeyer’s work examining the connection between modern right-wing conservatism and authoritarianism. Altemeyer, a retired psychology professor at the University of Manitoba, has studied authoritarianism for many years and is the author of “The Authoritarians” and “Enemies of Freedom: Understanding Right-Wing Authoritarianism.”

“Authoritarian Nightmare” effectively combines Dean’s knowledge of politics and the presidency with Altemeyer’s expertise in authoritarianism. The first hundred pages deal with Trump’s upbringing, business career and presidency, and cover some of the same ground as Mary L. Trump’s recent “Too Much and Never Enough: How My Family Created the World’s Most Dangerous Man.” Like her, Dean and Altemeyer consider Trump to be a narcissist with an incessant need for attention and praise who was indoctrinated by his authoritarian father “to intimidate and control others” and whose bullying behavior was evident even in childhood.

Trump is clearly an authoritarian leader, according to Dean and Altemeyer, but most of their book is devoted to examining and explaining authoritarian followers using psychological questions and personality tests. Altemeyer’s “RWA” scale measures how much someone believes in right-wing authoritarianism based on their responses to various statements. For example: “Our country desperately needs a mighty leader who will do what has to be done to destroy the radical new ways and sinfulness that are ruining us.” RWA followers strongly agree with this statement.

Those who score high on the RWA scale are submissive to authority but can be aggressive on behalf of that authority. They are conventional in their thinking and behavior, highly religious, have less education, are highly prejudiced against other groups, oppose equal opportunity, lack critical-thinking skills, and often hold inconsistent positions. They “have only a superficial belief in liberty and democracy,” the authors write. When authoritarians and their followers talk about how much they value freedom, they are talking about their own freedom — not that of others. They believe in being lenient if they and their leaders break the law but merciless against those they deem inferior, according to Dean and Altemeyer.

Altemeyer’s “social dominance orientation” (SDO) scale measures whether someone is a dominant leader — a type who desires personal power; thrives on inequality; cheats to win; and is amoral, bullying, vengeful, exploitive, mean-spirited and manipulative.

The study of authoritarianism was launched at the University of California at Berkeley during World War II when three psychology professors developed a personality test designed to identify potential authoritarians and understand why some people were drawn to them.

Among many others who have studied authoritarianism are Hannah Arendt, Yascha Mounk and Yale philosophy professor Jason Stanley, whose parents survived the Holocaust. In “How Fascism Works: The Politics of Us and Them,” Stanley argues that elements of fascism like white supremacy have been present in American politics for many years, and that fascists seek a “mythic past” that is “pure” in religion, race and culture, as well as a strong national leader who represents a “father figure.” Fascist leaders sow societal division and attack the truth with propaganda, Stanley writes.

There have been several tests of Altemeyer’s theories. Canadian universities in the 1990s conducted global crisis simulations using student participants. On the night when those who scored high on the RWA and SDO scales were tapped as national leaders, a hypothetical nuclear war broke out that killed most of the world’s population.

American state legislators were surveyed in the 1980s and 1990s to measure their RWA scores, and Republicans almost uniformly scored significantly higher than Democrats. The highest RWA scores in both parties came from representatives in Southern states.

Most relevant for the 2020 presidential election, Dean and Altemeyer worked with the Monmouth University Polling Institute in late 2019 to include questions in a nationwide survey of 1,000 voters that explored not only SRO and RWA levels but participants’ opinions about religious fundamentalism and ethnocentric prejudice, and their political views and affiliations.

The Monmouth poll overwhelmingly found that most Trump supporters are both highly authoritarian and highly prejudiced, and revealed that authoritarian views are deeply embedded in the belief system of many Republicans who would seek another strong leader to take Trump’s place whenever he departed the national political stage.

Trump’s followers don’t care about his dishonesty and questionable actions because their primary concern is the perceived corruption of the purity of American society, write Dean and Altemeyer. Trump’s base is oblivious to his unpresidential behavior, endlessly forgiving of his incompetence, and stands “ready to give Trump all the power he wants” in exchange for his promise to reverse societal change and protect them from the purported danger posed by “lawless” minorities and immigrants.

No matter what he says or does, Trump’s approval ratings have consistently stayed around 40 percent throughout his presidency thanks to the unwavering support of his base supporters.

The Dean and Altemeyer questions in the Monmouth poll found that many of Trump’s followers would support prosecution of his opponents. And when asked, a year ago, if Trump should continue as president if he loses the 2020 election but declares it fraudulent, 14 percent said yes and 19 percent said they weren’t sure. Dean and Altemeyer argue that 33 percent, the core of Trump’s base, stand ready to follow him anywhere.

Despite its many references to the psychological metrics, which provide the important evidence for Dean and Altemeyer’s argument, this is a very readable book. Those who want to try to understand Trump’s followers and what motivates them will find it important and alarming.

Like everything else with Trump, “Authoritarian Nightmare” is bound to elicit strong reactions. Those who don’t understand how anyone can still support the president will probably recognize some of their co-workers, neighbors and family members who do. Trump followers will inevitably dismiss it as more “fake news” because, as the authors contend, authoritarian followers have “a remarkable lack of self-awareness.”

If Dean and Altemeyer are right in their analysis, our country could be facing more strife and even existential challenges in the months and years ahead, and these dangers won’t end with Trump’s presidency.

Authoritarian Nightmare

Trump and His Followers

By John Dean and Bob Altemeyer

Melville House. 352 pp. $28.99