For millions of American evangelicals, a recent Oval Office photo-op was a perfect example of the political realities they face.

A day after his release from a Turkish prison, the Rev. Andrew Brunson knelt and prayed for the president who helped focus a global spotlight on efforts to free him. Brunson had been accused of backing critics of the Turkish regime.

The pastor asked God to give Donald Trump "perseverance, and endurance and courage to stand for truth. I ask that you to protect him from slander from enemies, from those who would undermine. … Fill him with your wisdom and strength and perseverance. And we bless him."

Millions of evangelicals, but not all, had to smile.

Trump, in jest, asked Brunson and his wife: "Who did you vote for?"

Millions of evangelicals, but not all, had to groan.

In the current news theory of everything, few numbers in American political life have received more attention than this one -- 81 percent of white evangelicals voted for Trump in 2016. Politicos have paid less attention to signs that many evangelicals cast those votes with reluctance, and some with a sense of dread.

"This was really a faith-based vote -- faith that Trump would operate as a conservative on the issues that mattered the most to evangelicals," said World Magazine editor-in-chief Marvin Olasky, a Christian conservative who, citing character flaws, openly opposed Trump getting the GOP nomination.

"I still don't like him at all, but I have to say that he's coming through. … It's a kind of politics by gesture, but he's pulling it off."

Praying with Brunson was "a perfect gesture," he added. But if Trump had "blown it on the Supreme Court, his support among evangelicals would have plummeted."

Before the election, World consulted 100 evangelical "leaders and insiders" and half of them said they wouldn't vote for Trump, "no matter what." The other half said they would watch for signals that Trump sent about the U.S. Supreme Court.

In another pre-election poll, the Pew Research Center found that 78 percent of self-identifying white evangelical voters planned to vote for Trump. However, only 30 percent said they were backing Trump, himself. Another 45 percent said they were voting against Hillary Clinton.

Similar tensions appeared in a recent LifeWay Research survey in which 51 percent of Protestant pastors approved of Trump's "job performance," with only 25 percent voicing strong approval. Pastors who called themselves "evangelicals" (63 percent) were more likely to support Trump than self-identified "mainline" Protestants (41 percent).

"It's still easy to see evidence that about half of the evangelicals who voted for Trump felt that they 'settled' for him," said Scott McConnell, executive director of LifeWay Research. "Lots of factors shape what people do when they feel that they have to vote for one candidate, or even cast a vote against another one."

In this poll, he added, asking about "job performance" was an attempt to let pastors distinguish between concerns about Trump's record ("What did he get done?") and his polarizing style ("How did he get it done?").

"For many evangelicals, if the WHAT is important enough, they're more willing to put up with the HOW, in terms of supporting President Trump," said McConnell.

The bottom line: Most "evangelicals by belief" (59 percent) have decided they will have to use their votes to support stands on specific political and moral issues, according to a new study by Wheaton College's Billy Graham Center Institute, working with LifeWay.

This time around, 50 percent of evangelical voters said they cast their votes to support a candidate, while 30 percent said they voted against a specific candidate. One in five evangelicals said they did not vote in 2016.

A Christianity Today survey analysis -- "Debunking the 81 Percent" -- put it this way: The 81 percent total represented "strategic, goal-oriented and issue-oriented" voting, not mere enthusiasm for Trump.

Waves of news about this 81 percent vote have "created a simplistic, negative caricature of who evangelicals are, right now," said Ed Stetzer, director of the Billy Graham Center. "It allows lazy people to keep saying that all of those evangelicals are 'all in' for Donald Trump. … They're trying to turn Trump voters into Trump.

"Trump voters are not Trump, and that's certainly true for most evangelicals."