NASHVILLE — At least since Martin Luther nailed his theses to the church door in 1517, Christians have disagreed on what Jesus calls them to do in the name of faith. There are nearly 34,000 Christian denominations worldwide, a number that doesn't account for American Christians — nearly one in six, according to a Gallup poll last summer — who belong to no denomination at all.

But as lively as Christian debate can be, the special Senate election in Alabama has exposed how closely conservative Christianity is now in lock step with the Republican Party. I grew up in Alabama, and I don't doubt the sincerity of my fellow believers on the other side of the political aisle, but when faithful Christians vote for a man credibly accused of child molesting, something is terribly wrong with Christianity. (With white Christianity, that is: Black Christians overwhelmingly supported the Democratic candidate, Doug Jones.) Eighty percent of white born-again Christians voting in Alabama backed Roy Moore, and there is no skirting the damage they've done to their own moral standing.

The day of the election, the editor in chief of Christianity Today, Mark Galli, identified the biggest loser in Alabama: Christian faith itself. From now on, Mr. Galli wrote, "When it comes to either matters of life and death or personal commitments of the human heart, no one will believe a word we say, perhaps for a generation."

Christianity presents a conundrum for evangelicals considering a monstrous political candidate who is also a Christian. The very foundation of our faith lies in the infinite mercy of a loving God, and it's hard for an ordinary sinner to cast the first stone. Last year I asked an evangelical friend how she could bring herself to support a presidential candidate like Donald Trump, whose behavior is so at odds with her own. "He says he's changed," she said, "and I believe in God's redemption. If I didn't, how could I get out of bed in the morning?"

I believe in redemption myself, though if I were in charge I think I'd be looking for evidence of repentance, too. And I'd be asking why people so deeply invested in redemption also tend to be so deeply invested in sending their fellow human beings to death row. But I'm trying to understand the country I've found myself in since last year's election, and these days I look hard for common ground.

It isn't easy to find. In her new book "Moral Combat: How Sex Divided American Christians and Fractured American Politics," R. Marie Griffith explains the divide between liberal and conservative Christians as a casualty of "the sex wars" — disagreements over women's rights, birth control, abortion and L.G.B.T. issues. By the time the Supreme Court's Obergefell v. Hodges decision legalized same-sex marriage in 2015, she writes, "the rupture between Christian antagonists in the sex wars felt irremediable: one could plausibly argue that Christianity had flat out split into two virtually nonoverlapping religions."

What Christians need is a new right-to-life movement, one in which we agree to disagree about contentious issues of sexuality and focus instead on what we share, on what we all believe. Jesus had nothing to say about birth control or abortion or homosexuality. He did have quite a lot to say about the poor and the vulnerable, and maybe that's a good place to start.Surely Christians across the political spectrum believe we're called to feed the hungry, heal the sick, protect the weak and welcome the stranger. If we can agree on that much, and if we can keep our shrieking differences from wrecking the quiet conviction of shared belief, we could create a culture of life that has a chance of transcending the sex wars. I find myself hoping for a day when conservative Christian voters can elect conservative representatives for whom feeding the hungry and caring for the sick and welcoming refugees aren't political issues at all.

Here in Nashville, through an ecumenical program called Room in the Inn, nearly 200 congregations of many faiths take in our homeless neighbors during the winter months. Every night from November through March, volunteers arrive at the program's base of operations downtown to pick up around 250 homeless people and drive them to area churches. Guests get a good meal, a hot shower and a clean bed for the night. The next morning they get breakfast and a sack lunch to take when another set of volunteers arrives to drive them back downtown. That night the cycle starts all over again with another set of congregations.

The other day, I found a toddler's sippy cup lodged between the seats in the third row of my minivan. Our youngest child is 19, and we have no grandchildren. I held it, puzzled, until finally it dawned on me: My husband had taken his shift at Room in the Inn the night before, and this cup must belong to one of the homeless families he drove to our church.

Homeless babies. The very thought is enough to make a person weep.

It's Christmas, the day Christians celebrate a baby wrapped in swaddling clothes and lying in a manger because there was no room for his family at the inn. We owe it to that infant to do better by the babies here among us. To do better by their parents, trying so hard to keep them fed and clothed and healthy. We owe it to him to throw open our arms and the doors of our inns. "You who are hungry and hurting and alone and afraid, come inside," we will say. "You belong here."

Margaret Renkl in The New York Times today, Christmas Day 2017.

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December 25, 2017