Shock. Betrayal. That’s the response that millions of Americans had after the 2016 presidential election when they learned that 80% of white evangelicals voted for Donald Trump. How could believing Christians vote for him in the first place, and then continue to approve of a presidency that has been marked by scandal, authoritarianism and racism?

Kristin Kobes Du Mez was shocked, too, but perhaps not as stunned as the rest of America. That’s because as a historian who teaches at Calvin University in Michigan, she’s been studying evangelicals for years. In the new book “Jesus and John Wayne: How White Evangelicals Corrupted a Faith and Fractured a Nation,” she says that evangelicals’ seduction by Trump has been coming for a long time.

They weren’t hoodwinked or misled by him, and they weren’t just holding their noses and voting for him to get anti-abortion Supreme Court justices. Instead, they like him. And they’ve been preparing for him for decades.

“Evangelical support for Trump was no aberration, nor was it merely a pragmatic choice,” Du Mez writes in the book. “It was, rather, the culmination of evangelicals’ embrace of militant masculinity, an ideology that enshrines patriarchal authority and condones the callous display of power, at home and abroad.”

Du Mez started connecting the dots of militant patriarchy and what she calls “family values evangelicalism” more than 15 years ago, when her students were passing around John Eldredge’s bestseller “Wild at Heart: Discovering the Secret of a Man’s Soul,” which encouraged a generation of Christian men to embrace their rugged, natural inner warrior.

The book sold millions of copies and joined other examples of a particular kind of masculinity that had long been promulgated by the Christian right, including books by James Dobson, Jack Hyles and Eric Metaxas. All of them connected Christian masculinity to violence or the threat of violence, from Dobson’s advice to parents to spank their children to Metaxas’ recasting of theologian Dietrich Bonhoeffer as a daring World War II spy.

“When I looked back historically, I could see how the militant masculine ideal was built up and embraced for decades,” says Du Mez. “If you go back to the 1960s and 1970s, this is a time when evangelicals were beginning to mobilize as a partisan political force, coming together as the religious right we know today. They were reacting against both the rise of feminism — they’re really emphasizing gender difference — and the Vietnam War.”

For evangelicals, she notes, Vietnam was a critical moment, because it pitted Christian America against the threat of communism, and America lost. “Evangelical Christians were deeply disturbed by this, and judged it as a failure of American manhood.”

In addition to feminism and communism, white evangelicals of the era spied another threat: desegregation. Particularly in the South, evangelicals’ political mobilization occurred around issues of race. “When you look at this, too, it was about asserting the authority of white patriarchy,” says Du Mez. “When you look at how they are justifying segregation, it’s about seeing white men as protectors of vulnerable white womanhood, and the rights of the family over and against the federal government. This militant evangelical masculinity that I write about is a distinctively white masculine ideal. And it is one that is justified, even if it includes violence. Given the threats, foreign and domestic, the idea is that God made men strong. He gave them testosterone to make them aggressive so that they can defend their family, their church and their nation.”

White evangelicals’ same three fears — the threats of feminism, war and racial equality — came into play in the 2016 election. They found the specter of Democrat Hillary Clinton as president terrifying enough that they gladly took cues from GOP candidate Donald Trump in chanting “lock her up” and labeling her a “feminazi.”

They craved a strong military in a post-9/11 era especially since now, unlike with the Vietnam War, the threat was on American soil. Trump played into their Islamophobia by promising a Muslim travel ban and promising to “bomb the sh-- out of” ISIS. And he played into their racial fears by blaming immigrants for many of America’s problems and claiming he would build a wall to forever end illegal immigrants from Mexico.

In short, Trump was telling white evangelicals what they had long wanted to hear.

Du Mez grew up in conservative white Christian circles and remains a practicing Christian, and says she was initially hesitant to study this topic in depth because she wondered if the “militant white patriarchy” strand of American evangelicalism might not just be a minority voice within the tradition. But the 2016 election showed her that the “Duck Dynasty”-watching, John Wayne-adoring crowd was not the fringe but the mainstream. They loved Donald Trump. His blunt militancy, his crassness, were not a bug but a feature.

While observers have wondered how evangelicals overlooked or quickly forgave Trump’s three marriages, multiple affairs and boasts of sexual assault, Du Mez says that evangelical culture has provided years of practice for this. Pastor after pastor has been embroiled in scandal, often involving sexual misconduct or other abuses of power.

“There’s such a culture of deference in evangelical churches and communities,” says Du Mez. Bill Hybels, the founder of the Willow Creek megachurch in the Chicago suburbs, conducted sexually inappropriate relationships with multiple women over the course of years before he resigned in disgrace; more recently at a California megachurch, pastor John Ortberg stands accused of covering up his son’s attraction to children and continuing to allow his son to do volunteer work with children at the church. And Mark Driscoll, the lead pastor of Mars Hill Church in Seattle, resigned in 2014 because of years of a “domineering style of leadership” and accusations of abusive behavior.

There is a common thread here, says Du Mez, though it’s more overt with people like Driscoll. “Mark Driscoll is the extreme example of this militant patriarchy. You can see it prominently in his writings on sex and gender, in his church leadership, his authoritarian style, his militarism, and how he really worked to generate a sense of threat within his own church.” Church members, she says, “were taught to fear the outside, and even to fear the church down the street, because there were enemies everywhere that were going to undermine truth.”

Driscoll has rebounded from his Mars Hill resignation and founded another church in Arizona, and he continues as a popular leader. Du Mez says this reflects the culture of white evangelicalism in propping up authoritarian male leaders. “Even after his downfall, you have a lot of his friends and admirers who are lamenting what happened to him because he was a ‘great Christian brother’ and ‘such a gospel witness,’ and not deconstructing his corruption of Christianity and seeing that that is where the problem was.”

Du Mez notes that evangelical culture often punishes people who call out abusive situations and toxic cultures, like Jen Hatmaker or Rachel Held Evans, which creates a climate of secrecy. For her part, however, she says she has not received much hate mail in the month since “Jesus and John Wayne” was published, despite the book’s clear denunciation of abuses of power.

“I have been overwhelmed by amazing letters of support,” she says. “I get several every day from evangelicals themselves — some who walked away, some who stayed in. These are heartfelt personal testimonies, almost all of which say something like, ‘This is the story of my life, but I never understood how all of these pieces fit together.’ There’s almost this catharsis of being able to name what happened and to understand that their own experiences were part of this much bigger story, and they weren’t alone in bumping up against the harsh edges of this ideology.”

Editor’s note The views expressed in this column do not necessarily reflect those of Religion News Service.