In 2021, religious figures capturing political headlines usually come from the far right. Their engagement ranges from pushing for restrictions on abortion and LGBTQ rights to relentlessly promoting former president Donald Trump. Most recently, right-wing pastors have offered to help people receive religious exemptions from coronavirus vaccine mandates in exchange for contributions. As midterm election campaigns kick off, religious conservatives will mobilize behind Republicans, looking to build on recent gains in places like Texas. While figures like the Rev. William Barber, who founded Moral Mondays, continue to agitate from the religious left, they have far less impact on national politics.

But it wasn’t always this way.

The power of religion to advance liberal goals was on display in an iconic photograph taken on March 21, 1965. Rabbi Abraham Joshua Heschel, walks arm in arm with prominent civil rights activists, including the Rev. Fred Shuttlesworth and Nobel Peace Prize winner Ralph Bunche. A nun on the other end of the front line of marchers is holding civil rights activist John Lewis, whose skull Alabama state troopers had fractured two weeks earlier during another march for voting rights. During the 1960s, Heschel, a professor at the Jewish Theological Seminary, stood at the nexus of religious leaders who linked tradition, theology and ritualistic practice to the fight against social injustice.

But in the 1970s, in the words of Rabbi Jill Jacobs, executive director of T’ruah, a liberal rabbinical association, the “Christian Right” claimed the “Public religious space.” Subsequently, even within Judaism, tensions over Israel have dominated political debates, while neoconservative voices have become pronounced.

Yet secular activists would do well to see the potential of the religious left. Religious leaders like Heschel imbued the push for liberal policy with a level of moral authority that benefited the social movements of the 1960s. Figures such as Barber offer an immense resource as liberals confront pushback from party leaders who worry their agenda goes too far and entrenched opposition from Republicans. Embracing the religious left could make social reforms far more achievable.

For Heschel, the Jewish tradition was deeply connected to the fight for social justice. An immigrant from Warsaw who had been forced out of Germany by the Gestapo in 1938, Heschel arrived in the United States in 1940 as part of a program to rescue European Jewish intellectuals.

Because World War II and the Holocaust left his mother and three of his sisters dead, Heschel understood intimately the devastation that could be wrought from a society that lost any foundation in moral or spiritual life. As he wrote: “Our world seems not unlike a pit of snakes. We did not sink into the pit in 1939, or even in 1933.” Rather, over generations, “the snakes have sent their venom into the bloodstream of humanity, gradually paralyzing us, numbing nerve after nerve, dulling our minds, darkening our vision. Good and evil, which were once as real as day and night, have become blurred mist.”

Heschel’s theology pointed him toward engaging the struggle for a better world. “Some are guilty,” he wrote, “but all are responsible.” During the 1950s, Heschel wrote books about the relationship between God and man. God, he said, looked for pious humans who could open themselves up to his voice and hear what worried God about the state of humankind. Heschel’s “The Prophets” (1962), depicted the Hebrew prophets as acutely sensitive to injustices and horrors that most people didn’t even see.

Heschel closely followed the social struggles unfolding in the United States. In 1958, he called for fellow rabbis to support the civil rights cause. He was inspired by the Christian preachers who were at the forefront of the movement and the way that the church played such a pivotal role in mobilization and protest.

His first major foray into activism occurred at an interfaith conference on religion and race in 1963. Accepting an invitation from Martin Luther King Jr., Heschel powerfully reminded his audience that a person could not be religious and racist because “racial or religious bigotry must be recognized for what it is: satanism, blasphemy.”

Heschel’s growing friendship with King led to the rabbi speaking at interfaith civil rights gatherings, attending protests in New York and Washington and ultimately ending up on the streets of Selma where he felt like his “legs were praying.”

Heschel railed against individuals who stood on the sidelines. “There is an evil which most of us condone and are even guilty of, indifference to evil,” he wrote. “We remain neutral, impartial, and not easily moved by the wrongs done unto other people. Indifference to evil is more insidious than evil itself.”

Meeting the weight of his own words, Heschel’s activism extended beyond civil rights. Starting in the early 1960s, he helped lead organizations putting pressure on the Soviet Union to allow Jews behind the Iron Curtain to practice their religion and live free of fear. He implored other rabbis to take a bolder stand on this issue. “There is no sustained action,” he warned, “no program of informing or impressing upon our own people … of being witness to spiritual genocide.” Heschel’s advocacy helped to spawn a movement that generated global pressure on the Soviets.

Additionally, Heschel helped found the Clergy and Laity Concerned About Vietnam, which brought together preachers and rabbis who believed America’s military intervention in Southeast Asia was both inhumane and immoral long before the antiwar movement took hold in the late 1960s.

On Feb. 6, 1968, Heschel walked alongside King in front of 2,500 protesters in a “procession of agony” at Arlington National Cemetery. The protesters walked in somber silence until Heschel and King reached the steps in front of the Tomb of the Unknowns.

King, who came out against the war during a CALCAV event a year earlier, proclaimed, “In this period of absolute silence, let us pray.” After six minutes, Heschel broke the silence by reading from Psalm 22 in Hebrew: “My Lord, My Lord, why hast Thou Forsaken me?” This Psalm was traditionally understood to be a cry of supreme anguish chanted when a person appealed to a head of state. Christians considered it to be the final words uttered by Jesus Christ. Bishop James Shannon followed Heschel by saying, “Let us go in peace. Amen.” The march later returned to New York Avenue Presbyterian Church, where King closed out the day by speaking about the moral collapse of America and the despair African Americans felt as money went to kill Vietnamese rather than help cities.

Heschel’s activism — and that of other religious figures from all faith traditions — contributed a moral dimension to the liberal activism of the 1960s. The ability to stir people’s consciences helped to achieve key civil rights gains, brought about the collapse of public support that limited the Vietnam War and helped save Jews behind the Iron Curtain.

Restoring the central place of liberal religious activism in American political life is crucial in 2021.

At Selma, Heschel lamented the fact that Jewish religious institutions had not capitalized on a golden opportunity to cast the civil rights movement “in terms of Judaism.” Even most Jews actively participating were “totally unaware of what the movement means in terms of the prophetic traditions.”

Today, this lamentation offers a blueprint for bringing morality and spirituality to the crusades for social justice, against climate change and for gun control, among others. Preachers have the capacity to reach audiences who are otherwise disconnected from these debates. By rooting political issues in questions about faith and spirituality, they can elevate and illuminate how questions about protecting the environment or ending police brutality, for example, matter to all of humankind.

While many liberals have grown weary of religion in politics because of the legacy of right-wing Moral Majority founder Jerry Falwell and others like him, Rabbi Jacobs and Rev. Barber, as well as Rabbis David Saperstein and Jonah Pesner of the Religious Action Center of Reform Judaism, have been at the forefront of reconnecting spirituality and social, racial and economic justice. They and others have made immense progress crafting a new era for the religious left. Sen. Raphael G. Warnock (D-Ga.), a pastor, has literally bridged the two worlds. And Pope Francis has also helped create an opening by speaking forcefully about issues such as climate change and economic inequality.

They understand that only people on the left praying with their legs can balance the role of religion in politics.