The latest of these is a Jewish scholar, Rabbi Abraham Joshua Heschel, who was born in Poland and later managed to flee Nazi Germany to the United States, where he flourished amid a society willing to turn an ear toward the top religious voices of the day.

Doblmeier's film "Heschel" makes its debut May 5 on public television stations nationwide, although individual stations may choose to air the hourlong documentary on another date.

The Virginia-based Doblmeier was filming interviews for "Heschel" last year while he was on the road doing promotional events for his documentary on Catholic Worker Movement co-founder Dorothy Day, another of his preservationist documentary subjects.

Doblmeier had done about half of the promotional stops on the Dorothy Day tour before the coronavirus pandemic effectively shut down much of the United States. But he had wrapped up the final "Heschel" interview two weeks before the pandemic was declared.

Some archival material was never able to be procured, and those stills and film clips he did obtain took far longer than usual to make their way to him, he told Catholic News Service in an April 16 phone interview.

Doblmeier noted how many of Rabbi Heschel's biggest contributions came later in life; the rabbi died in 1972 at age 65. He is often seen in photos standing in the front line of the advancing protesters with the Rev. Martin Luther King Jr. as they cross the Edmund Pettus Bridge into Selma, Alabama.

The rabbi also argued to bishops attending the Second Vatican Council against rolling back on language in its declaration "Nostra Aetate," on the Church's relations with non-Christian religions, that would have continued to encourage the conversion of Jews.

Doing a documentary on Rabbi Heschel had "been on my mind for a long time," Doblmeier said. "I did a film four years ago on Reinhold Niebuhr, the great American theologian, and how Niebuhr became this close, close friend of Abraham Joshua Heschel."

The two men worked "literally across the street from each other," Niebuhr at Union Theological Seminary in Manhattan and Rabbi Heschel at Jewish Theological Seminary.

Despite the obvious denominational differences, each man thought he was appreciated more by the other than by their fellow faculty at their respective institutions, according to Doblmeier – to the point that they agreed that whoever died first, the other would preach at the funeral, which Rabbi Heschel did when Niebuhr died in 1971.

One of the interview subjects for the Niebuhr documentary was Susannah Heschel, Abraham's daughter. Doblmeier said Susannah asked him, "When you finish doing your film on Niebuhr, would you consider doing a film on my father?"

Doblmeier has done films on a diverse range of figures, from Dietrich Bonhoeffer, the German theologian who was part of a conspiracy to kill Adolf Hitler, to Cardinal Leo Jozef Suenens, the Belgian cardinal who was a key voice during Vatican II.

"One of the differences, especially between then and now, in the '50s and '60s in particular, we were very interested as media in getting the opinion of people we viewed as moral figures," Doblmeier told CNS. "Heschel and other people had this national reputation because the national media talked to them: 'What do you think about nuclear weapons? What do you think about the economic plans for this country?'

"There are people today who I think are doing prophetic work, but they're not getting the same kind of attention. We don't look to those voices, we don't pay attention to their voices. And that's our loss," Doblmeier said.

"Sister Norma Pimentel down at the border," he continued, referring to the Missionary of Jesus sister who heads Catholic Charities of the Rio Grande Valley in Texas. "She's as Dorothy Day-like a figure as I can think of. She gets significant press in the Catholic community, but in the wider media, not so much."