President Donald Trump leaned on overwhelming support from white evangelical Christians in the 2016 election, capturing 81 percent of their vote and again affirming their conservative bent.

Republicans can expect more of the same this midterm election. More than 80 percent of white evangelical voters said they'll vote for their Republican candidate for Congress on Tuesday, according to a survey by the Public Religion Research Institute (PRRI).

But will that voting bloc remain reliable for the right for years to come? Numbers show white evangelicals are shedding young followers put off by the culture war waged by their parents and grandparents.

Young evangelicals overall are more likely to hold liberal views on same-sex marriage, the environment and immigration compared with older evangelicals, Pew Research Center found in 2017.

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Even at Liberty University, a bastion of young Christian conservatism, plucking a red-meat Republican from the crowd isn't a lock.

"This is one of the biggest conservative Christian campuses ever, and it's still very divided," said Lindsey Longhorn, 18, a Liberty sophomore who said she's like-minded with Trump on certain immigration issues but leans pro-choice on abortion and backs same-sex marriage.

Liberty sophomore Konner Burke, a registered Independent who voted for Trump, finds himself mulling left-leaning policy "more and more every day."

Burke acknowledges the Bible's stance on same-sex relationships but argues that "it's not really my business" and supports his position with religious logic.

"How am I supposed to cast a stone when I have so many problems with me?" he asked.

Evangelicals, as defined by the National Association of Evangelicals, blend a serious belief in the Bible, a born-again transformation and a sense of activism. But today's young voters grew up in a more secular America with more cultural diversity, said Molly Worthen, an associate professor at the University of North Carolina specializing in American religious history.

Some are simply exhausted by their parents' politics, she explains.

"They are put off by the sense that the old-school moral-majority style of culture-warrior politics means a conservative white evangelical is always spoiling for a fight, is intolerant and unwilling to listen to differing opinions," Worthen said. "All of that runs counter to the broad message that evangelical young people have absorbed from the culture."

Political identities are hard to shake

Despite cultural influences, if you're waiting on young white evangelicals to turn on Republicans and push a wave of Democratic victories this midterm election – don't hold your breath.

PRRI data show 78 percent of white evangelicals 18 to 29 are Republicans or Republicans that lean Independent. More than three-quarters of them plan to vote Republican on Tuesday.

Politics is a lot about identity, not issues, and changing identity is difficult, said Stephanie Martin, an assistant professor at Southern Methodist University who specializes in public discourses of conservative social movements.

"Their parents may buy wholly into the idea that the Republican Party is the party of family values, and a young evangelical might see through that, might see it as a ruse, but still be a Republican because that was the culture and the milieu and the way of being in the world that they grew up in," she said. "The likelihood that they're going to break from that is pretty low."

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Luke Dillard, a 22-year-old Liberty senior who voted for Trump, couches his political views with a preamble about his faith and upbringing in a conservative household. He believes abortion is murder and holds the Bible's man-and-woman view on marriage.

"They're, like, super-conservative," he said of his parents. "I wouldn't say that I'm full-on, hard-core conservative."

Like Dillard, senior Amari Mitchell uses her childhood to support her views. Except she was raised a Democrat, voted for Hillary Clinton in 2016 and finds no trouble uniting her political beliefs and her faith.

"I just keep my belief in God," she said.

Dillard, who is white, and Mitchell, who is black, exemplify the drastic political split between white and non-white evangelicals. The difference is so stark that it's imperative the groups be separated when studying them, said Robert P. Jones, CEO of PRRI.

While the large majority of white evangelicals voted for Trump in 2016, black Protestants voted 96 percent for Clinton, according to Pew.

"There's a fundamental divide in evangelical America with regard to race," said Janelle Wong, a professor of American studies at the University of Maryland. "In some ways, on many issues, white evangelicals couldn't be more different from Asian-American, Latino and black evangelicals.

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"Oftentimes in their ethnic communities, they're not the dominant group," she said. "They are socialized in these places that have become very blue."

Trevor Thomas, a 25-year-old Liberty graduate student who wrote in Sen. Ted Cruz for president on his 2016 general election ballot, decries the U.S. immigration process, which he described as expensive.

"I'd like to live in a world where the rule of law is obeyed but at the same time compassion is given," said Thomas, whose parents are Jamaican immigrants. "I don't think this country has to be so law-abiding-minded that it abandons people."

Earlier this year, the National Association of Evangelicals, which represents more than 45,000 churches, publicly urged Trump to halt the practice of separating migrant families at the border.

Waning clout

Experts argue it's not young white evangelicals following a change of heart that poses a threat to Republicans – it's that overall white evangelicals' dwindling numbers could render them politically insignificant.

"White evangelical protestants have certainly been a powerful force in American politics for a couple of generations since the '80s and (Ronald) Reagan, but their clout in the general population is waning over the last 10 years," Jones said. "There’s been a bigger loss at the younger end of the spectrum.”

In 2008, white evangelicals comprised nearly a quarter of the U.S. population. That number is now 15 percent, according to PRRI, and the remaining ranks are held together by a graying group. The median age of white evangelicals is getting older and is now 56.

Meanwhile, just 8 percent of those 18-29 identify as white evangelical, according to PRRI.

"It's a small, small group, particularly if you're going after younger voters," Jones said. "From a strategy point of view, there are richer targets out there."

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So will the GOP face a reckoning at the ballot box?

Not quite yet.

"The religious right, as a network of very savvy political institutions, will continue to punch above its weight politically for decades," Worthen said. "Even as we see that secularizing trend persist, it will not likely immediately translate to a huge turnout of votes for progressive political candidates."

Jones agrees that white Christians are "over-represented at the ballot box."

"The ballot box acts a little bit like a time machine that takes us back about 10 years in terms of the composition of this country," he said. "White Christian Americans tend to vote at a pretty high rate."

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Worthen says the evangelical generation gap is actually nothing new. But Trump exacerbated the existing chasm between young and old evangelicals.

"We're just paying even more attention to it now because it seems like the stakes are so high," Worthen said. "That conflict is livelier. There are more young white evangelicals going public with their dissent. They're still a minority, but I do think there are more of them now."

Follow Sean Rossman on Twitter: @SeanRossman