SOUTH BEND, Ind. — Religious conservatives who have long been a reliable voting bloc for Republicans are grappling with a new challenge in Pete Buttigieg: how to respond to a Democratic presidential candidate who is leaning into the discussion about faith and its role in political life.

For years, Democrats seeking inroads with religious voters have faced a major obstacle erected by evangelicals and other conservative Christians who have often portrayed resistance to socially conservative policies as attacks on people of faith. Adding to their challenge is the fact that few Democratic candidates have seemed comfortable emphasizing their personal faith, perhaps unsurprising given that their positions on abortion, LGBT rights and contraception differ from traditional religious orthodoxy.

Buttigieg, who formally declared his candidacy on Sunday, is flipping the traditional Democratic playbook by emphasizing how scripture informs his positions on those same issues, rather than shying away from the topic.

Using vocabulary familiar to religious conservatives, he has constructed his arguments in a way designed to allow voters to conceive of supporting him and his approach as affirming — rather than challenging — a strong belief in God and religious values.

“We have this totally warped idea of what Christianity should be like when it comes into the public sphere, and it’s mostly about exclusion,” Buttigieg said recently on MSNBC’s “Morning Joe.”

“Which is the last thing that I imbibe when I take in scripture in church.”

He describes his own same-sex marriage in moral terms, saying that his union with his husband has made him a better man and brought him “closer to God.” His ascent to the national political stage has coincided with shifting political winds in the U.S. at least on gay rights, with polls showing that a majority of Catholics and white Protestants now support same-sex marriage, and moral condemnation of gays and lesbians is considered acceptable by a smaller segment of American society.

Tony Perkins, president of the conservative Family Research Council, rejected the notion that evangelicals in particular would be swayed by a candidate like Buttigieg. Still, he acknowledged that religious Americans who are more liberal would find his message particularly compelling.

“They perceive in him less hostility. They might not see things the way evangelicals do, but faith is still important to them,” Perkins said. But, he adds, when it comes to evangelicals, "he's going to have a hard time because there's a disconnect between the talk about faith and actual biblical principles.”

In past elections, the notion of a disconnect was an easier argument to make. Then-Sen. Barack Obama, when he first ran for president in 2008, notoriously stumbled when remarks he made at a fundraiser were published in which he said Americans from small towns “cling to guns or religion” as manifestations of their economic anxieties. Hillary Clinton only rarely mentioned her own Methodist faith during her 2016 campaign, and her primary opponent, Bernie Sanders, who is Jewish, said he wasn’t particularly religious.

Buttigieg, who was baptized Catholic and attended a Catholic high school but now attends an Episcopal church, has said that his faith does guide his behavior in public life, and that the lessons he draws from scripture are “about lifting up the least among us and taking care of strangers, which is another word for immigrants, and making sure that you’re focusing your effort on the poor.”

“Republicans do not have a viable successful playbook for dealing with Democrats that are willing and able to make a positive case around faith, and that is what Buttigieg has done pretty consistently,” said Michael Wear, who was the faith outreach director for Obama’s 2012 campaign and author of "Reclaiming Hope.”

“He hasn’t gone negative. Most of the time when he talks about faith it’s the positive things in his life and the positive vision it gives him for governing," Wear said. "It’s left Republicans pretty flat-footed."

The uncertainty about how to speak about Buttigieg and his candidacy has played out in religious conservative circles and on the internet with increasing urgency as Buttigieg has surged in the polls and criticized Vice President Mike Pence for supporting religious liberty bills that limited LGBT rights. Pence and many supporters responded by accusing Buttigieg of attacking Pence’s faith.

The emerging strategy for responding to Buttigieg centers on emphasizing his positions on specific issues that remain a litmus test for many conservative voters, most notably abortion and gay marriage.

Erick Erickson, an evangelical radio host and conservative writer, posited on his blog The Resurgent that Buttigieg “apparently thinks Jesus would be ok with bestiality.” He based that on the logic that Jesus never addressed bestiality, and that Buttigieg has defended his support for abortion rights by pointing out that Jesus never discussed abortion. In another post he took aim at Buttigieg’s religious fidelity, arguing that since he’s Episcopalian, “he might not actually understand Christianity more than superficially.”

And after Buttigieg accused evangelicals of hypocrisy for backing Trump despite personal behavior that would make many churchgoers cringe, Christian writer Michael Brown wrote on the anti-abortion site LifeSiteNews that it was “absurd” for a “professing Christian and practicing homosexual” to point fingers at others.

“As an out-and-proud gay man, Buttigieg must discard the entire testimony of Scripture, since every single reference to homosexual practice in the Bible is condemnatory, without a single positive, homo-sex affirming statement of any kind,” he wrote.

Buttigieg’s biggest challenge with religious conservatives may be his support for abortion rights, which are still opposed by majorities of U.S. evangelicals, Baptists and Mormons, according to a 2017 Pew Research Center survey. The South Bend mayor told the Rev. Edward Beck, a Roman Catholic author, in a CNN interview this month that he doesn’t see “how my intervention as a government official, making rules about what she can and can't do, is going to help.”

Bob Vander Plaats, a prominent Iowa political activist and president of the group The Family Leader, said he and other social conservatives welcome the nascent focus on faith and religion in the 2020 conversation. He said when it comes to casting votes, religious conservatives would find Buttigieg’s policy positions simply untenable.

“Donald Trump will stand up for the sanctity of human life and the sacredness of life and the unborn child. And Pete Buttigieg and others will say, ‘No, I'm OK with abortion on demand, and even maybe a born-alive bill,’ which is completely contrary to the Christian faith,” Vander Plaats told NBC News.

He added: “That's the opportunity for the conversation, because once we peel back that onion, it'll be very, very clear: There is nothing in the scriptures that back gay marriage, there's nothing in the scriptures that would back embracing a gay lifestyle.”

Democrats seeking to peel away religious voters have significant ground to make up. In 2017, Pew found that the Republican advantage has only grown in recent years among evangelicals, with 77 percent of white evangelicals either identifying as Republicans or leaning in that direction. White Catholic voters and Mormons also leaned Republican by clear majorities.