(Bloomberg View) —The religious left is the Sasquatch of American politics. It leaves footprints in the snow but recent sightings of the creature itself are rare, and not always credible.

Progressive politics is dominated by secular ideals and, increasingly, secular voters. In recent decades, the words “Christian” and “evangelical” have been commandeered as synonyms for “white conservative.” Religious liberals never achieved the power of their conservative opposites. In a bit of denominational trash talk, Russell Moore, the president of the Ethics and Religious Liberty Commission of the Southern Baptist Convention, said to the Atlantic in 2013: “Where are the Unitarian mega-churches, the Episcopalian church-planting movements?”

The once-explosive growth of conservative evangelicals has stalled. Yet the religious left doesn’t appear to be benefiting much. Instead, the ranks of the religiously unaffiliated are growing. A 2016 report by the Public Religion Research Institute stated: “Today, one-quarter (25 percent) of Americans claim no formal religious identity, making this group the single largest ‘religious group’ in the U.S.”

Yet if ever there were a moment for the left to seize the mantle of religion from conservatives, surely it arrives Jan. 20 at noon. Donald Trump received the votes of four in five white evangelical or born-again Christians. Hypocrisy is as old as humanity, but even hypocrisy has a gross weight limit.

Christian conservatives are now inextricably tied to an incoming president with a long, public history of exploiting the weak, and no documented history of charity, faith or Christian communion or witness. They have endorsed a First Lady whose modeling career included a pornographic photo shoot described by the Trump-friendly New York Post as “girl on girl.” Even among the plaster saints of the religious right, Trump is a heavy burden to bear.

Sojourners is one of the groups seeking to rally the religious left. “Our Constitution’s protection of religious freedom empowers faith institutions to oppose state-sanctioned bigotry and violence and creates strong sanctuaries for those Jesus called the ‘least of these’ in Matthew 25,” said Lisa Sharon Harper, chief church engagement officer of Sojourners, in an e-mail. Liberal churches are already announcing themselves as sanctuaries for undocumented immigrants fearing deportation. There appears to be a Trump-related bump, likely temporary, in attendance at liberal churches.

A coalition of groups has launched the “Matthew 25” initiative to fight an expected barrage of federal policies targeting the most vulnerable — including the poor, immigrants and Muslims. “These people are organizing under the banner of Jesus,” Harper said.

In North Carolina, the liberal “Moral Mondays” movement has been partially credited with the election in November of Democrat Roy Cooper as governor. The success of the movement — named for weekly public demonstrations against the conservative legislature and incumbent governor — is a powerful precedent. It gained momentum not only because of charismatic religious leadership, but because of unusually aggressive Republican efforts to undermine voting rights and cut funding for education and services.

A similarly harsh agenda from Trump and congressional Republicans could be a catalyst for reviving the religious left nationwide. “If you can create a coalition that includes the religious left but also those moderates in the middle and also secularists, then you would have an incredibly strong coalition,” said Marie Griffith, director of the John C. Danforth Center on Religion and Politics at Washington University in St. Louis.

It’s less hard to imagine such a broad coalition taking shape than it is to imagine it fighting, Tea-Party-style, to actually gain power. “Unlike the religious right, which is almost entirely the Christian right, the religious left is a diverse interfaith movement,” e-mailed Robert Jones, author of “The End of White Christian America” and the CEO of PRRI. “And this more diffuse and diverse group presents serious organizational challenges — both in terms of visibility and impact. And at least so far, the institutional infrastructure and leadership challenges are still very much in development.”

Religious movements often require inhospitable terrain to thrive. As Roger Finke and Rodney Stark wrote in “The Churching of America 1776-1990,” power and prestige often suck the energy from religious groups while marginalization strengthens them. Successful religious insurgencies, they wrote, “impose significant costs in terms of sacrifice and even stigma upon their members.”

Trump’s regular shocks to decency, along with an expected Republican assault on funding for the poor, will outrage both secular liberals and the religious left. But will that be enough to bring the left’s religious Sasquatch out of hiding?

“It will be years before we can understand the magnitude of what just happened in the 2016 election,” wrote Griffith in the Danforth Center’s policy journal. “In the meantime, we will not normalize the hate that has received an epically consequential public platform. Roll up your sleeves, friends; there is work for all of us to do.”

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.