Since the founding of the republic, there have been dozens of Protestant ministers in Congress, and a handful serve right now. Two Catholic priests, too, have served in the House of Representatives. But despite the large number of Jews elected to Congress, not once has a rabbi been elected. In fact, only two have ever run, and neither had much of a chance: In 2012, pop-advice author, television rabbi and Michael Jackson confidant Shmuley Boteach lost badly in his New Jersey district, and in 2008 Dennis Shulman — who got a great deal of attention for being blind and thus a rare disabled candidate — lost to a popular incumbent, also in New Jersey.

Which means that Robert B. Barr, who plans to file papers today to be a Democratic candidate for the House of Representatives in Ohio’s 1st District, is notable not only for being that rarest of birds, a running rabbi, but also for being the first who seems to have a good shot at winning. If he is the eventual nominee, his opponent would be Republican incumbent Steve Chabot, who lost once already, in the Obama landslide of 2008, before reclaiming his seat in 2010.

Barr, 62, is at once the most traditional rabbi (of the three) ever to run for Congress, and the least. He’s the most traditional because he has been a pulpit rabbi, at Congregation Beth Adam, outside Cincinnati, since 1980 — doing weddings, burials, bar mitzvahs, the whole megillah. By contrast, Boteach, a rabbi of the Lubavitcher Hasidic sect, was primarily a celebrity  who hosted the reality TV show “Shalom in the Home,” on which he used Jewish wisdom to help dysfunctional families get along better. In Shulman’s case, although the media focused on his rabbinic calling, he was a long-term psychotherapist who got ordination later in life  and never led a congregation.

At the same time, while Barr’s professional life looks rabbi-ish (to coin a term), his Judaism is seen, by some, as well outside the mainstream. Although ordained a Reform rabbi, Barr founded a congregation, Beth Adam, that belongs to none of the major branches of Judaism. It is widely identified with what’s loosely called humanistic Judaism, a small movement in which Barr is considered a leader. The congregation uses prayers that omit any mention of God, and its teachings tend to emphasize science and human reason above spirit or metaphysics. And Beth Adam welcomes members who are not Jewish, even by conversion.

Of course, there are plenty of atheists, and agnostics, in all branches of Judaism; one might say that humanist congregations are unique only in treating those beliefs as no weirder than any other take on God. Barr, for his part, won’t say what he is, or isn’t, in terms of God-belief.

“I’m not an atheist,” Barr said, in an interview yesterday. When asked what he does believe, he demurred. “My relationship to God has always been private. Everyone should have that right. I have never made the congregation about my personal beliefs.” Rather than be a forum for its rabbi’s beliefs, the congregation he founded aims to “respect the diversity of beliefs people have,” supporting them in their search for what kind of god they believe in, if any.

Running for office was very much an extension of his calling to the rabbinate, Barr said.

“I have been thinking on and off for my lifetime about running,” Barr said. “But in the last election, I was more and more disturbed by the divisiveness. I felt I had a responsibility to do something about it. I said, ’37 years I have been a rabbi, been trying to repair the world, and I have a responsibility to run now.’ ”

Hasia R. Diner, who teaches Jewish history at New York University, said that historically rabbis have seen it as prudent to stay out of politics.

“American Jews always maintained that there was no Jewish vote and that rabbis ought to stay above the partisan fray,” Diner said. “They for the most part believed that at least vis a vis the realm of Judaism as a religious framework, the best bet was to appear neutral and to reach out in that vein to both parties.”

Barr’s principal issues include “repairing the damage that has been done” by the Trump administration, as well as “comprehensive campaign finance reform,” he said. “We need to deal with health care,” which for him means repairing, not repealing, the Affordable Care Act. And, he added: “Our responsibility is leaving the world better than we found it. That means the environment needs to be taken care of, and I don’t see that happening.”

If he wins, Barr, the longest-serving pulpit rabbi in greater Cincinnati, would join a growing community on the Hill of the religiously skeptical, humanist or unaffiliated, including Rep. Kyrsten Sinema of Arizona, now running for Senate, who is religiously unaffiliated; Sen. Tammy Baldwin  of Wisconsin, who refuses to give a religious affiliation; and Sen. Mazie Hirono of Hawaii, a “nonpracticing Buddhist.” And if he loses? Then the next rabbi will have to hope that the fourth time is the charm.

When its application to join the Reform movement was rejected in 1994, Congregation Beth Adam was widely described as “humanistic.” Today, Barr rejects that label. He says that Beth Adam is an “independent, liberal” congregation, and not a member of the Society for Humanistic Judaism. Its nontheistic liturgy, written over the years by the congregation, “is an expression of who we are and what we believe,” Barr said. “It gives voice to Judaism’s ever-unfolding religious experience and promotes the humanistic values of intellectual honesty, open inquiry  and human responsibility.”

“Just to recap — I grew up Conservative, trained at [Hebrew Union College-Jewish Institute of Religion], studied with an Orthodox rabbi and have always drawn from multiple streams of Jewish thought in my rabbinate.”

Mark Oppenheimer hosts the podcast “Unorthodox,” Tablet Magazine’s weekly talk show and roundup of “the news of the Jews.”