The Rabbinical Council of America, the largest organization of Orthodox rabbis, is likely to initiate an inquiry into alleged moral improprieties of its member, Rabbi Marc Schneier, the high-profile spiritual leader of The Hampton Synagogue in Westhampton, L.I., and New York Synagogue in Midtown, whose success in drawing wealthy and loyal supporters and congregants is matched by his widely reported history of personal romances.

Faced with the choice of resignation or the likelihood of being brought before the RCA’s Vaad Hakavod, a committee to deal with the personal conduct of members, Rabbi Schneier this week chose not to step down.

The impetus for the RCA’s involvement in the matter is a spate of recent stories in local tabloids reporting on an alleged affair Rabbi Schneier was conducting this spring while still married to his fourth wife.

At an RCA executive committee meeting Sept. 1, the officers unanimously recommended the highly unusual step of investigating a member’s actions, with the possibility of disciplining or expelling him.

“This would be a call for an inquiry,” the RCA’s first vice president, Rabbi Shmuel Goldin, told The Jewish Week on Tuesday. At issue, he said, is whether Rabbi Schneier’s actions represent a chillul hashem, or desecration of God’s name, in terms of “behavior of a public or private nature unbecoming a rabbi,” which the group views as grounds for discipline.

The RCA inquiry, should it go forward, is not expected to harm Rabbi Schneier’s standing at The Hamptons Synagogue, which he founded in 1990 and where Shabbat services regularly attract up to 1,000 worshippers. It includes a full schedule of activities during the summer months, from adult education classes and famous authors to Jewish film festivals.

One prominent supporter of the synagogue said it continues to thrive and that most congregants feel a strong sense of loyalty to the rabbi. “He’s a great guy, and we’ve chosen to forgive him,” he said. “He’s just not good at marriage.”

Rabbi Schneier made headlines in The Daily News — “Rabbi To The Stars Caught Kissing Another Woman In Israel,” Aug. 14 — after his fourth wife, Tobi Rubinstein-Schneier, who is seeking a legal separation after four years of marriage, is alleged to have charged in court papers that he is having an affair with a congregant — and that the woman is pregnant with the rabbi’s child.

Supporters of the rabbi insist that the woman, identified as Gitty Leiner, a speech pathologist, is not a congregant and has never been pregnant, offering a letter to The Jewish Week from a physician as proof. They add that the rabbi and his present wife are separated.

Rabbi Schneier is expected to assert to the RCA that his publicly acknowledged bipolar condition is the cause of what friends describe as his “erratic behavior,” and that he should not be punished as a result.

Asked by The Jewish Week for a comment, the rabbi released a statement, through his public relations representative, Matt Dorf, on Tuesday afternoon, saying:

“Rather than support one of its 25-plus-year members in a time of medical need, the RCA has instead embarrassed itself by listening to tabloid smears and innuendo spread by a soon-to-be ex-wife looking to shake down her third husband.

“Rabbi Schneier looks forward to a vigorous defense against this smear campaign that the RCA itself has regrettably given voice to.”

The Vaad Hakavod, should it be convened, would have the latitude to determine whether Rabbi Schneier should continue to function at his synagogue, take a leave of absence until his condition is improved, be expelled from the RCA or decide on another alternative.

The last time the Vaad Hakavod was called into action was in 2004 when it launched a yearlong investigation into allegations of sexual impropriety against Rabbi Mordechai Tendler of Monsey, who was expelled in 2005.

Rabbi Schneier, who congregants say functions as a combination of spiritual leader, celebrity and impresario, has become a national figure over the years.

The Hampton Synagogue’s website calls it “New York’s Most Celebrated Synagogue,” and Rabbi Schneier was ranked by Newsweek as among the 50 most influential rabbis in America. He is also the founder of the Foundation for Ethnic Understanding, an organization advocating racial harmony and chaired by hip-hop star Russell Simmons. He has championed the cause of Jewish-Muslim dialogue in recent years.

Since The Jewish Week began making inquiries last week about what, if any, response there was among rabbinic groups regarding Rabbi Schneier’s behavior, the newspaper has received calls from a variety of advocates for the rabbi, including his friends, supporters, public relations spokesmen and medical experts.

Two of the rabbinical groups with which Rabbi Schneier was involved seemed inclined to stay out of the fray.

Asked for comment, Rabbi Joseph Potasnik, executive Vice President of the New York Board of Rabbis, which Rabbi Schneier has led as president, demurred, saying, “It’s a private matter.”

Similarly, initial inquiries to the RCA, whose policy guidelines insist that “rabbis must conduct themselves in ways that are exemplary in their religious, moral and interpersonal conduct,” went unanswered for several days.

This was followed up by an e-mail message from the RCA’s executive vice president, Rabbi Basil Herring, who wrote:

“We are saddened to see a member of the RCA in this situation. We will have no further comment at this time.”

The muted response was noteworthy, given the RCA’s swift and outspoken criticism of other members over the years for issues of halachic adherence.

In recent months, the rabbinical group reprimanded Rabbi Avi Weiss of the Hebrew Institute of Riverdale for giving a woman associate the title of “rabba,” and at the time of the Obama inauguration, it criticized Rabbi Haskel Lookstein of Congregation Kehilath Jeshurun in Manhattan for participating in a prayer service in a Washington church honoring the president.

One RCA official acknowledged that the group felt goaded to take action in the case of Rabbi Schneier, because “how would it look if we ignored this kind of behavior” that has received so much attention. “If left unaddressed, it might cause many to question the high moral standards the RCA expects from its members,” he said.

Another RCA member said the group sought to be sensitive to Rabbi Schneier and his medical issues, but did not want to give the impression that a medical condition provides a rabbi an excuse to act improperly.

“If [Rabbi Schneier) said to us, ‘I have a problem and I can’t serve my congregation until I’m better,’ I’m sure we wouldn’t take action. But he seems to want to continue as if everything is fine.”