"I caution against the idea that the way to get young people into church is to be hip and cool and have a pastor who wears skinny jeans." Rachel Held Evans could have been talking about any number of much-hyped contemporary evangelical congregations: the Fellowship Church in Grapevine, Texas, for example, whose pastor started a website called PastorFashion.com, or Mars Hill, the Seattle megachurch that dissolved amid controversy in 2014, but left behind a large network of congregations. Many of the fastest growing churches in America are exactly what Evans describes: Places with Sunday morning rock bands and chic websites and pastors who occasionally, yes, wear skinny jeans.

So there's irony in her wry caution: Young people may be leaving the church, but for the most part, evangelical Christian churches are not the ones they're leaving.

Evans is not a woman to back down from a good church fight, though. "I think there are some evangelicals who are eager for me to quit bothering them," she said in an interview. As a popular blogger and the author of books about topics like sexuality in the church, she has gotten into many an Internet tussle. But perhaps no topic invites anxiety like Christianity's decline in America—and lo and behold, her new book, Searching for Sunday, is all about "loving, leaving, and finding the church." She was looking for a certain kind of message, which may resonate with others in a generation that came of age after 9/11, lived through two wars, and not-so-happily endured years of recession: a recognition that life is dark.  

Her book comes at a challenging time for church life in America. Many denominations are steadily losing members. More and more people aren't affiliating with any religion, including a third of those born between 1980 and 2000—"the single most common religious identity among this generation," according to the Public Religion Research Institute.

But more importantly, "Christianity is losing a little bit of its death grip over the culture," Evans said. Sliding numbers, along with cultural and political battles over issues like same-sex marriage, have helped cultivate a sense of persecution or defensiveness among some Christians. "There’s a sense that the culture is shifting," she said. "That can be fearful for some people."

The interesting thing about this, though, is that an overwhelming majority of Americans still identify as Christians—roughly 75 percent. Church life is still very much part of American life, which is why the frame of Evans's book is so useful. She writes of growing up in an evangelical congregation in Tennessee, quitting church in her twenties, planting and closing a new church before she turned 30, and finally settling into an Episcopalian congregation—for now—at 33. Hers is a first-person account of what it's like to struggle with the existence of God and hate church politics and still yearn, a little or a lot, for the kind of community that religious worship can bring. After she and her husband decided to leave Grace Bible Church, the congregation Held grew up in, over the issue of same-sex marriage, "I put my head in my hands and cried, startled to tears by the selfishness of my own thoughts," she wrote. "Who will bring us casseroles when we have a baby?"

Many Millennials may not go to church, but like Evans, they have a church story. These stories don't come out in demographic data, which obscures an experience that a lot of young Americans probably have: "No one really teaches you how to grieve the loss of your faith. You're on your own for that," Evans writes. For those who are trying to figure out where they fit, she just doesn't believe that punk-rock Christianity will do the trick of getting people back in the pews.

"The reasons Millennials are leaving are more complex than a lack of cool," she said in an interview. "We’ve been advertised to our entire lives. We can smell B.S. from a mile away. So if you’re just trying to sell us a product, we can tell.”

Although Evans's book is not directly about Millennials leaving the church, she talks a lot about that topic, for she is a Millennial who once left the church. She gives some credence to the cultural shifts that have made certain theological concepts difficult to parse in public—as she puts it, "I'm as uncomfortable as the next Honda-driving, NPR-listening, New York Times-reading progressive with the notion of exorcising demons." She also takes issue with the gender politics in certain parts of the church; with Mars Hill, for example, "the exterior was hip and edgy, but they made the old mistake of authoritarian leadership," she said in an interview.

But two issues stand apart from the others. The first is unsurprising: LGBT acceptance. "I grew up being told that people chose to be gay and that it was a sin," Evans said. Over time, her views changed to match those of many of her Millennial peers—in 2014, two-thirds of Americans born after 1981 said they supported gay marriage. "If you’re turning away gay people, we’re going to see through the hip B.S.," Evans said.

This is not true of every church in America, of course. In March, the Presbyterian Church of the U.S.A. voted to allow gay marriages, and organizing bodies of the United Church of Christ and the Evangelical Lutheran Church had previously decided the same. But overwhelmingly, Christian denominations do not allow same-sex marriages in their churches, and some preach a strong theology against homosexuality: the Baptists, the Catholics, the Mormons, the Methodists. In her book, Evans describes attending a conference of the Gay Christian Network, many of whom were evangelicals who had left or been asked to leave their churches. "'I remember the first time I was called a ... homophobic word,' said a young woman, no more than twenty, who wore a flower in her hair and kept her eyes on her shoes. ... 'It was at a church.'" This, Evans said, is the issue that will define the church experience of many young Christians.

The other major theme that emerges from her book is a little more surprising, although it probably shouldn't be: sin. "A lot of liberal, progressive people are afraid of the word sin," she said in an interview. To some, the idea of a flawed human nature which leads to transgressions against God might be the same category as exorcisms—part of the "bizarre truth of Christian identity," as Evans puts it.

But even for regular church-goers, she said, sin may not be something many readily embrace. "Why do we mumble through rote confessions and then conjure plastic Barbie and Ken smiles as we turn to one another to pass the peace?" she writes. "What makes us exchange the regular pleasantries—'I'm fine! How are you?'—while mingling beneath a cross upon which hangs a beaten, nearly naked man, suffering publicly on our behalf?"

Some of this is cultural, she said—the idea, particularly in the ever-hospitable, perfectly polished South, that you should "bring your best self to church." But "even in faith communities that aren’t Southern, there can still be that pressure to perform, and be Instagram-y, and not be honest and talk about your sin," she said.

That's why upbeat music and stylish services don't do it for Evans: Hers is a Christianity that is fully aware of darkness. "So much of what Christianity produces as far as books and literature and even music in our worship—it’s all very rosy, when that’s not really life, and that’s not really church," she said. "We carry the weight of many, many centuries of injustice, and that matters, and we can’t just ignore that."

That might sound cynical, but it doesn't sound much like B.S. It's also not a pat plan for reinvigorating Millennial life in the church. Other than making space for those who wish to worship, Evans said, she isn't worried about who fills church pews. "Death is a thing empires worry about, not a thing resurrection people worry about," she said. "As long as there’s somebody baptizing sinners, breaking the bread, drinking the wine; as long as there’s people confessing their sins, healing, walking with one another through suffering, then the church is alive, and it’s well."