L'église c'est moi?

The conservative Christian coalition that helped usher President Trump into power in 2016 is planning its largest midterm election mobilization ever, with volunteers fanning out from the church pews to the streets to register voters, raise money and persuade conservatives that they cannot afford to be complacent this year.

But the cumulative weight of scandals in Mr. Trump’s private and public life is threatening to overshadow what the religious right sees as its most successful string of policy victories in a generation. And Republicans will be up against not only a resurgent liberal opposition to Mr. Trump but also the historical disadvantages that burden any party in full control of Washington, especially in the first off-year congressional elections of a president’s term.

“The midterms are going to be very, very tough for the Republicans,” said Robert Jeffress, who leads the First Baptist Dallas megachurch and is one of Mr. Trump’s most loyal evangelical supporters.

Mr. Trump, to date, has been accused by a pornographic film star and a Playboy playmate of conducting separate affairs shortly after his wife, Melania Trump, gave birth to their son. Those controversies, paired with the multiple women who accused him of groping them before the election and his own boasts of sexual aggressions, have put a spotlight on the evangelical movement and its unyielding support for the president. Critics in other parts of the Republican tent — and a few among evangelical leaders — are asking just how much obscenity, belligerence and bigotry Christians should accept.

“Now even the Christian culture is O.K. with it,” said Jim Daly, the president of Focus on the Family, one of the nation’s largest evangelical groups. “That’s the sadness,” he added. “The next time a Democrat in the presidency has a moral failure, who’s going to be able to say anything?”

But Christian conservatives contend that Mr. Trump has also more than honored his end of the bargain that brought reluctant members of their ranks along during his presidential campaign. He has begun the process of moving the American Embassy in Israel to Jerusalem, won the confirmation of numerous judges and a Supreme Court Justice who seem likely to advance their anti-abortion cause, moved against transgender protections throughout the government, increased the ability of churches to organize politically and personally supported the March for Life.

“I don’t know of anyone who has worked the evangelical community more effectively than Donald Trump,” said Ralph Reed, the chairman of the Faith and Freedom Coalition, which this year plans to devote four times the money it spent in the 2014 midterms.

In essence, many evangelical leaders have decided that airing moral qualms about the president only hurts their cause.

“His family can talk to him about issues of character,” said Penny Young Nance, the president of Concerned Women for America, an evangelical organization that is framing the midterm elections to potential donors as a civilizational struggle.

So far, the decision by most conservative evangelical leaders to double down on their support for Mr. Trump is playing out like most of the other moments when skeptics of the president believed he had finally undermined himself with his base.

A poll released last week by the Public Religion Research Institute found white evangelical approval for Mr. Trump at its highest level ever: 75 percent. Only 22 percent said they had an unfavorable view of the president.

Much as in the 2016 presidential campaign, Christian conservative events are designed to be highly visible and to convey the movement as one united voice. Hundreds of evangelical leaders plan to gather in June at the Trump International Hotel in Washington for a conspicuous show of support for Mr. Trump. The event will be part pep rally, part strategy session.

In the states, leading religious and socially conservative groups will be propped up by the Republican National Committee, which will encourage voter registration at churches and schedule round tables with local pastors and evangelical liaisons close to the president.

Some of the organizers call themselves “the watchmen on the wall,” a reference to guards who looked over Jerusalem from the Book of Isaiah.

The message to energize Christian conservatives has twin purposes: to inspire them to celebrate their victories and to stoke enough grievance to prod them to vote.

But in a midterm election, no singular political enemy will emerge the way Hillary Clinton did in 2016. Instead, leaders of the movement plan to lean hard into a message that fans fears and grudges: that the progressive movement and national media mock Christian life and threaten everything religious conservatives have achieved in the 15 months of the Trump administration.

“Show the left that you can put labels on us, you can shame us. But we’re not giving up,” said Tony Perkins, the president of the Family Research Council, who explained that many conservatives of faith see attacks on Mr. Trump as an attack on their judgment.

The Family Research Council has already activated its network of 15,000 churches, half of which have “culture impact ministries” that organize congregations to be more socially and civically engaged. The group’s efforts will gear up with voter registration drives around the Fourth of July and voter education that will focus on a half-dozen states that could determine control of the Senate.

Their tactics are almost identical to the work they used during the presidential campaign to unite a fractured evangelical base. The June meeting in Washington is a follow-up to a gathering in New York in the summer of 2016 that soothed tensions after it became apparent that Mr. Trump would be the Republican nominee.

Leaders of the Christian right have not only largely accepted Mr. Trump’s flaws and moved on; they seem to almost dare the president’s opponents to throw more at him. Ms. Nance said she heard a common sentiment from volunteers and supporters who did not seem bothered by the allegations of Mr. Trump’s infidelity. “We weren’t looking for a husband,” she said. “We were looking for a body guard.”

Concerned Women for America’s fund-raising pitch claims, “This is our Esther moment,” referring to the biblical heroine whose resourcefulness saved Persia’s Jews from annihilation hundreds of years before Jesus. The group plans to have get-out-the-vote organizers in 10 states where Democrats are defending Senate seats in states where Mr. Trump won.

Mike Mears, the Republican National Committee’s director of strategic partnerships and faith engagement, described the midterm campaign as “a call to arms.”

“You like what the president is doing?” he asked. “We need your help.”

The danger for Republicans is the many evangelicals who do not like what the president is doing. His petty insults, coarse language, lack of humility and private life are difficult to square with Christian faith, opponents say. The president has helped devalue character, morality and fidelity as essential qualities in political leaders, they say.

A meeting of evangelical leaders in Illinois last week featured a frank and candid discussion of the president’s failings, prompting some pro-Trump attendees to walk out.

But for evangelicals loyal to Mr. Trump, the criticism is irrelevant. They say that as challenging as the political realities may be, they remain hopeful that voters understand what is at stake. “We are living in unusual times,” said Jerry Falwell Jr., the president of Liberty University and one of Mr. Trump’s earliest evangelical supporters. “And after what happened in 2016, I think anything is possible.”