Last September, we contrasted Donald Trump and Jimmy Carter and asserted that Trump would never be president. We stand by that forecast, though Trump has defied the predictions of all who dismissed his candidacy as a sideshow farce. In fact, his campaign has turned out to be a frightening and dispiriting headliner act. With Trump now the Republican front-runner, the nation faces the prospect of a general election featuring a demagogue who appeals to base emotions and prejudices. He embarrasses his party and the country.

Trump’s candidacy once seemed certain to fail, in part because, it was thought, evangelical Christians would shun him. Devoid of civility and grace, Trump flaunts personal characteristics evangelicals surely would find repellant: boastful and vulgar, bullying and dishonest, insulting and bigoted, misogynistic, a purveyor of crass racial stereotypes, an inciter of violence. Yes, evangelicals are diverse, and many serious ones have rejected Trump. But enough have embraced him that the conservative Protestant subculture now occupies a spot on the list of those whose reputation Trump has tarnished.

“I’m a very good Christian,” Trump says, in the same flippant, childish way that he has said he would be the “most presidential” president since Lincoln and that he doesn’t need foreign-policy advice because “I have a very good brain.” His wild promises and reckless accusations stand upon nothing, utterly lacking evidence and denying the facts. Yet he shamelessly asserts that under his imagined reign of perfection, everything that is now “terrible” will become “beautiful.” Christians will be happy because store clerks will say “Merry Christmas” instead of “Happy Holidays.” A Trump decree will make it so. Christians will have taken their country back.

If this type of dull promise wins the loyalty of evangelical voters, Trump’s immature idea of Christianity is matched by his supporters’ shallowness. If Trump himself is a nominal Presbyterian, so must vast numbers of his supporters surely be no more than nominal evangelicals. David Gushee of Religion News Service has observed that Trump appeals to an anti-intellectual, anti-elite strand of American Christianity. He resembles prosperity-gospel preachers who push the heresy that God rewards faith with wealth and success.

Similarly, Ross Douthat of The New York Times asserts that Trump taps into a vein of evangelicalism that was “Trumpian already — nationalistic, prosperity worshiping, by turns apocalyptic and success-obsessed.” Followers of this version of faith feel under attack by secularism and seem eager to cast their lot with an authoritarian strongman who promises to protect them.

Among the Trump campaign’s revealing incidents was a clash with Pope Francis. Asked about Trump’s promise to make Mexico pay for a border wall, Francis said that “a person who thinks only about building walls, wherever they may be” is not acting like a Christian. Trump’s apologists said the pope should not have questioned the businessman’s faith. But Francis was right: Trump’s words, and the attitudes they revealed, did not befit a Christian. Francis was speaking not only of Trump but of the need for each of us to consider whether we are wall-builders or bridge-builders. As one who has washed the feet of the downtrodden, Francis has earned the right to express an informed opinion about such words and attitudes.

The same duty belongs to American voters: to evaluate the character of a self-professed “very good Christian” who would deport millions of immigrants, ban Muslims from entering the country, torture suspected terrorists and punch protesters in the face.