AMNA NAWAZ: More than a quarter of Americans now claim no religious affiliation.

That's according to the Pew Research Center.

That group now comprises the largest bloc of Americans and follows decades of declining attendance among white Christians, as well as Black Protestants and Jews.

Judy Woodruff reports that, for white Christians, there's also been a growing political divide within some faith communities.

It's her latest installment of America at a Crossroads.

JUDY WOODRUFF: Across America, each week, a familiar sound, Christians of different denominations gathering to sing, worship and find community.

Yet, in a growing number of places in the country, especially away from major cities, that sound has been growing softer.

And, in some, like this American Baptist church in Southern Illinois, which has existed in some form since 1868, it will soon grow quiet altogether.

RYAN BURGE, Eastern Illinois University: I have done a handful of baptisms while I have been pastor here, but I have done over 25 funerals.

So we're just not offsetting the losses at this point.

And once you get to a certain point, it's almost impossible to pull out of the nosedive.

We have had a bunch of birthdays because we haven't been really meeting last couple of weeks.

JUDY WOODRUFF: For more than 17 years, Ryan Burge has been the pastor of First Baptist Church ABC in Mount Vernon, one of the many mainline Protestant denominations that once dominated the nation's cities, towns and countryside.

Yet, since 1972, even as the country's population has grown over 60 percent, the proportion of white Americans attending churches like these or even identifying as a Christian has fallen precipitously.

This church will close for good in July.

RYAN BURGE: Religion is just not a central part of life for lots and lots of people.

Today in America, about 25 percent of people report weekly church attendance, which puts us on par with a country like Italy.

We were above 40 percent at one point.

Amongst Catholics, 50 percent were weekly mass attenders in 1972.

It's 20 percent today.

So we're seeing a decline in religious attendance across almost every religious tradition, not just Protestants, but also Catholics as well.

And Jesus answered, very truly, I tell you, no one... JUDY WOODRUFF: In addition to being a pastor, Burge is also a political scientist teaching at Eastern Illinois University, where he studies the intersection of faith, politics and the data behind it, describing these broad trends in his 2023 book, "The Nones," about the growing share of Americans who identify as atheists, agnostics, or nothing in particular.

RYAN BURGE: Ninety percent of Americans used to identify as Christians in 1972.

It's about 65 percent today.

And the share of Americans who are white Christians is now below half.

The nones have gone from -- N-O-N-E-S -- have gone from 5 percent of America in 1972 to almost 30 percent of America today.

Amongst young people, it's over 40 percent of America.

So we're facing an entirely different religious landscape today than we did even 30 years ago.

JUDY WOODRUFF: What is your best understanding of what's happened, why fewer and fewer Americans feel some connection with a church or with a faith?

RYAN BURGE: I think a lot of it is that Americans are anti-institutional now.

And if you look at data and trust in institutions, we don't trust anything today as much as we trusted it 40 years ago, whether it be banks or unions or the media or religion.

They're not seeing the value that religion plays in people's lives.

And they're also thinking -- and I think this is the thing that I push back against the most -- that religion is only about belief.

Religion is also a social enterprise.

You come here, you sit next to people who are different than you.

You learn how to volunteer, you learn how to run meetings, you learn how to fund-raise.

You learn about the Bible, but you also learn that other people are good people.

MAN: How about some pulled pork?

JUDY WOODRUFF: Just a few miles away, some of those volunteers are helping the needy at this once-a-month-food pantry, Angels on Assignment, where they provide free food, clothing and help with expenses.

The population of Jefferson County is shrinking as it ages, and its politics have swung further to the right, in 2000, voting 54 percent in favor of George W. Bush to nearly 72 percent in favor of President Trump in 2020.

Volunteers here joined from across local denominations, but this outreach is organized by another mainline denomination in steep decline.

The United Methodist Church has fallen from 11 million people in 1967 to half of that today, and, in just the past two years, lost about a quarter of its churches over issues surrounding same-sex marriage and LGBTQ clergy.

REV.

VICTOR LONG, First United Methodist: The lord's table is the place where the distinctions between rich and poor, powerful and powerless, are erased.

JUDY WOODRUFF: On a recent Sunday morning, though, First United Methodist pews were mostly full, with more joining online, and a full choir leading the congregation, including Keith and Cheryl Cox.

CHERYL COX, Member, First United Methodist: One more time.

JUDY WOODRUFF: A decade ago, Keith, a retired choir director, and Cheryl, a former German teacher and school administrator, moved from Northern Illinois to the family farm here.

The first church they joined closed, with too few members to sustain it.

The next one, a Methodist Church close to home, didn't align with their views on supporting border migrants through UMCOR, the church's relief agency, and the decision to close churches during the COVID-19 outbreak.

KEITH COX, Member, First United Methodist: When I was on the church council and I heard the church leaders in that council being very unhappy about the fact that UMCOR was helping migrants, and that the bishop was a terrible person for trying to keep people safe, that truly troubled me.

And so I was not as interested in being a part of that church at that point in time.

JUDY WOODRUFF: Now Keith and Cheryl drive 45 minutes each way twice a week to sing in the choir and worship at First United Methodist in Mount Vernon.

KEITH COX: It's the best 45-minute drive that I have on a regular basis, because I do feel uplifted when I go to the church.

And I can't say that that's been true even at the other Methodist churches that I have been to.

JUDY WOODRUFF: And recognizing that politics was now a part of the church set of beliefs, how did that make you feel?

CHERYL COX: I think politics has invaded schools and health care and just about every aspect of our lives.

So I shouldn't be surprised that it is invading in some ways in the church.

But did it make me feel uncomfortable?

Absolutely.

JUDY WOODRUFF: Singing alongside Keith and Cheryl Cox is Seth Calvert, who was drawn to this church first by its music, then by its message.

REV.

VICTOR LONG: The lord's table is the place where gay and straight and every other orientation in between can discover and receive the gift of God's life-giving grace.

SETH CALVERT, Member, First United Methodist: It honestly kind of rocks my world that there are people who are Christians who are actually open-minded.

JUDY WOODRUFF: Calvert lives in Mount Vernon with his husband, Brandon (ph).

He was raised Southern Baptist, but felt increasingly uncomfortable with that branch as he aged, especially as he heard things from the pastor that conflicted with his realization that he was transgender.

SETH CALVERT: One of the examples that actually was the reason I ended up leaving that church was, he was going on a tangent about how trains rights was all bad and all that.

And he said the civil rights movement was a mistake because now we have the gay rights movement.

And it was like, that's wrong.

JUDY WOODRUFF: You were hearing that, and then what were you thinking?

SETH CALVERT: I had been taught, if you see things going wrong, you always stay there and try and fix them.

And that's what I was trying to do for years and years in that church.

And then it got to the point that it's like, there's no way I can fix this.

There's no way that me sticking around is going to be able to help these people see that what they're saying and doing is wrong.

REV.

VICTOR LONG, First United Methodist: It's almost like we have become a safe haven for refugees from other traditions and even other United Methodist churches who have felt excluded.

JUDY WOODRUFF: Victor Long leads this congregation of the United Methodist Church, whose motto is "Open Minds, Open Hearts, Open Doors."

REV.

VICTOR LONG: The churches they often come from are very rigid and narrow.

And, now, some have come from churches where politics was really the theme of the messages they heard.

And they're looking for a safe place where they're not told what to believe, where they have freedom to ask questions, and room to grow in their faith.

JUDY WOODRUFF: On the day we visited, long delivered a sermon the importance of unity.

REV.

VICTOR LONG: The lord's table is the place where Democrats can kneel alongside Republicans.

Where else in the world are you going to see that?

I just felt like it was the right time for people to be reminded of that.

And communion is the perfect setting for it, because that's when we come together as one and receive the bread and wine.

JUDY WOODRUFF: And when you say it's the right time, what's made it the right time, do you think?

REV.

VICTOR LONG: Because all the other voices that get airtime in the church are about division and who's right and who's wrong and we need to leave.

And people need to hear that I believe Christ calls the church to unity, in spite of our differences.

It's not uniformity, but it's unity in the body of Christ.

JUDY WOODRUFF: Long says his congregation includes Republicans, Democrats and everything in between, a hallmark of mainline Protestant churches.

But that is becoming increasingly rare, according to Ryan Burge.

RYAN BURGE: For a long time, we always thought that religion was the first lens and politics was downstream of that.

So, what party I voted for, I looked at the Bible, I think about theology, how I view the world, and then I picked Republican or Democrat.

Now things have changed.

The recent data says that we pick our religion based off our politics.

So, if I'm a Republican, I'm going to seek out a congregation that affirms my views and really tells me what I want to hear.

So that's why a lot of people have left religion over the last 50 years.

So even today, amongst liberals, 50 percent of them are non-religious.

Among conservatives, it's only 12 percent.

So what we're seeing more and more is people go, well, I can't do that.

JUDY WOODRUFF: In our next story, we will visit an evangelical church in Tennessee that has leaned heavily into politics and President Trump, but is now having second thoughts.

For the PBS "News Hour," I'm Judy Woodruff in Mount Vernon, Illinois.