At Temple Beth El, in Cedarhurst, L.I., a soon-to-be-married interfaith couple might be presented with a mezuzah to acknowledge their upcoming union. The Jewish partner might be called up to the Torah for an aliyah. But the honor would not be called an aufruf, and the couple would have to go elsewhere to exchange their vows.

At Greenburgh Hebrew Center, in Dobbs Ferry, Westchester, the rabbi will guide interfaith couples throughout their wedding preparations, welcome their children at the Hebrew school and involve both parents’ families in the bar or bat mitzvah service. But for the wedding ceremony, Greenburgh Hebrew Center’s rabbi will direct the couple to a Reform colleague.

“As much as I can be there for the family in helping to walk them through the process without actually officiating, I am happy to always do,” said the congregation’s spiritual leader, Rabbi Jay Stein. But, he said, “I still believe rabbis should only perform in-faith marriages.”

Such is the balancing act of a Conservative rabbi at a time of increasing intermarriage, and as the movement’s market share has plummeted. That balancing act, one that requires the movement to reconcile the warring impulses to uphold tradition and practice inclusivity, is being tested anew lately.

In November, the Rabbinical Assembly, the rabbinical arm of the Conservative movement, expelled veteran Rabbi Seymour Rosenbloom for performing interfaith weddings. In March, the membership of the United Synagogue of Conservative Judaism will vote on whether to allow congregations to admit non-Jews as members. There is no movement-wide rule against non-Jews holding officer positions, although many individual congregations have such rules.

“I think that in the history of Conservative synagogues in North America, certainly in this generation, this is a major topic,” Rabbi Joshua Rabin, United Synagogue of Conservative Judaism’s director of innovation, told The Jewish Week in a telephone interview. He says he thinks the motion will pass. “We’ve been gathering information about this from our congregants for a year. By and large, I think that our synagogues are trying to turn a corner on this just as we are.”

Indeed, the Rabbinical Assembly, the Jewish Theological Seminary and the Ziegler School of Rabbinic Studies have already endorsed the motion.

The question of whether rabbis should be allowed to perform interfaith marriages is more fraught.

“The Conservative movement is torn between two conflicting positive imperatives,” said Steven Bayme, director of the Contemporary Jewish Life Department of the American Jewish Committee. “Given the reality of mixed marriage, it’s of enormous importance that mixed marrieds be considered as welcome, as included. … That said, the other imperative is that the best solution to mixed marriage remains conversion to Judaism. And for those who are not married, the imperative of that is inmarriage,” he said. “You’re torn between these two conflicting imperatives of upholding the values of endogamy and conversion on the one hand and welcome and inclusivity on the other hand. Those two things don’t coexist all that easily. … I think it’s a real challenge for the movement.”

According to a 2013 study by the Pew Research Center, the intermarriage rate for Jews has risen from 46 percent in the early ’90s to 58 percent in 2013. The majority of those marriages are by Reform (50 percent) and unaffiliated (69 percent) Jews; in 2013, 27 percent of Conservative Jews were married to someone outside the fold, the survey said. Only 2 percent of Orthodox Jews marry non-Jews, the survey found.

In most streams of Judaism the issue of interfaith marriage is clear-cut. Reform and Reconstructionist rabbis are free to perform interfaith marriages, intermarried couples are welcomed and children with Jewish fathers and non-Jewish mothers are considered to be Jewish. The Orthodox world rejects interfaith marriages outright. Conservative synagogues, on the other hand, occupy a gray area, where tolerance is balanced with tradition, and rabbis are left walking the tightrope of adhering to halacha while still trying to be welcoming to those who marry outside the fold.

“We all recognize that we live in an open society and people fall in love with the people they fall in love with,” said Rabbi Julie Schonfeld, executive vice president of the Rabbinical Assembly. She says that while everyone agrees that interfaith families are a “really valued part of Jewish community and that … incorporating them into our communities is something that we care about and take pride in. … We are rabbis of a halachic philosophy of Judaism. So we do all of those things very vigorously within the limitations that our religious beliefs afford us, within the bounds of halacha.”

Since 1972, when the Rabbinical Assembly’s Committee on Jewish Law and Standards was asked to make a ruling on the question, the assembly has maintained that rabbis are not allowed to officiate, participate in or attend marriages between a Jew and a non-Jew.

“Even though that means that we are not officiants of the weddings of some of the people we care a lot about … we want very much and feel that we are to be available in people’s lives,” Rabbi Schonfeld said. “That’s really the balance and the struggle. … And one thing I can tell you for sure is that there’s no rabbi in this organization that doesn’t feel it very deeply.”

Rabbi Rosenbloom opted for inclusivity over endogamy.

A Conservative rabbi for 44 years, Rabbi Rosenbloom, 72, officiated the marriage between his stepdaughter and her non-Jewish fiancé in the summer of 2014, shortly after he retired from Congregation Adath Jeshurun near Philadelphia. Since then he has performed four additional intermarriages and plans to conduct two more. The R.A. had given him the option of avoiding expulsion by promising not to perform any more interfaith weddings, but Rabbi Rosenbloom declined the offer, telling The Jewish Week in a telephone interview that his decision to perform interfaith weddings is “a matter of conscience.”

“That this is part of my mission as a rabbi, to be mekarev, to bring people closer to the community,” he continued, “and I believe that no matter how welcoming we are after the marriage, the sting of the rejection is often the only thing couples will remember when you say no.”

He argues that any two people who want a rabbi to officiate at their wedding is already interested in making Judaism part of their lives. At that juncture, a rabbi’s response will either “keep the door open for them” or “slam the door in their face,” he said.

The Conservative movement’s positions are constantly changing, and preceding each shift — ordaining women as rabbis, performing gay marriages — there is the same debate over whether it will cause the movement to lose its distinctiveness, he said.

“I’ve heard these arguments time and time again and ultimately history overwhelms these artificial boundaries, and the reality is that we accede to the reality of the world in which we live.

“The movement is in trouble frankly, but I don’t think it’s because we have changed too much; I think it’s often because we changed too slowly, because we don’t have the courage of our convictions, and because we are constantly worried about whether what we do is going to diminish our standing as a movement,” he said.

During his four-plus decades as a Conservative rabbi, Rabbi Rosenbloom said, his approach has veered “toward more inclusiveness rather than less. We really need to have compelling reasons to do anything that would restrict those values.”

It’s hard to tell what percentage of Conservative rabbis feel as Rabbi Rosenbloom does. A 2015 survey by Big Tent Judaism, an organization that promotes the embrace of intermarried families, found that 40 percent of respondents said they would officiate at interfaith weddings if permitted to do so. Conservative leaders, including the R.A.’s Rabbi Schonfeld, dismissed the findings as “unrepresentative,” because the results are based upon a self-selected group of 249 rabbis, out of some 1,700 who chose to fill out the survey. Percentages aside, the survey makes clear that there are 99 Conservative rabbis in North America who say they want to marry interfaith couples. It also makes clear that there are at least 152 that don’t.

Rabbi David Wolpe, senior rabbi of Sinai Temple in Los Angeles and a Jewish Week columnist, no doubt speaks for many when he explains his reasoning for not performing interfaith marriages.

While he says he understands why so many rabbis support the idea, he personally would never do it for two reasons: The first, because research shows that inmarried Jews are more likely to raise their children as practicing Jews than intermarried Jews — a recent study puts the percentages at 96 percent compared to 20 percent. “You’re presiding over something that, as a category, is destructive of that which you’re giving your life to.” The second is that “because one person involved is not subject to Jewish law, the presence of a rabbi at a Jewish legal ceremony is an adornment alone.”

Rabbi Jay Stein, head of Greenburgh Hebrew Center in Westchester, agrees. While it’s possible for an intermarried Jew to maintain a strong sense of his or her own religion, “sometimes,” Rabbi Stein said, “that doesn’t happen.”

“I think that what happens in an interfaith marriage is that there is unfortunately in some cases the opportunity for people to lose track of who they are entirely,” he said. “I think that being Jewish is an extremely powerful way to live and I would hate to see that lost.”

Rabbi Matt Futterman, head of Temple Beth El of Cedarhurst (L.I.), wrote in an email that while he feels there is a clear need to “embrace” non-Jewish parents, “as Jews, we need to balance that sensitivity with a commitment to such core beliefs as the primacy of halacha in guiding the decisions of the Conservative movement.

“We need to accept our people as they are and where they are, but officiating at intermarriages would indicate that we have diluted Conservative Judaism to a commemoration of traditions instead of a principled philosophy reflecting our version of the ongoing dialectics we maintain with God via the paths and tools shaped by Halacha,” he wrote.

Rabbi Steven Kane of Congregation Sons of Israel in Briarcliff Manor in Westchester believes that the Conservative movement should be allowed to officiate interfaith marriages as long as the couples agree to certain standards, such as committing to take a basic Judaism class and raising their children as Jews.

“Weddings are unique moments in the life of a family and how we treat and relate to them at that particular moment, when they are seeking religious guidance, can well be determinate for how Jewish the family unit will be in the future,” he wrote in an email.

United Synagogue of Conservative Judaism, the congregational wing of the Conservative movement, received a grant in May through a program aimed at interfaith family engagement jointly funded by the Genesis Prize and the Jewish Funders Network.

United Synagogue’s Rabbi Rabin is working with congregations to help them find ways to make interfaith families feel welcome. “The goal is to make everyone who wants to be engaged in the community feel engaged in the community,” he said.

Some synagogues have created special sections on their websites that outline for interfaith families what rituals they can, and cannot, take part in. Congregation Adas Israel’s website boasts a video where non-Jewish partners discuss how comfortable they feel at the Washington, D.C., congregation. Some congregations have affinity groups for interfaith families.

“It varies from synagogue to synagogue, but all of those things are part of a toolbox that Conservative synagogues make use of,” Rabbi Rabin said.

The Federation of Jewish Men’s Clubs, a Conservative movement umbrella group, has been promoting tolerance of interfaith families for nearly two decades, holding overnight and daylong retreats for rabbis to discuss the issues. Rabbi Charles Simon, the organization’s executive director, estimates that 300 rabbis have taken part.

“There are many Conservative rabbis who would like more flexibility in order to fashion a response to intermarriage and do it in a way that’s appropriate to them and their community — and not be tied by the … Rabbinical Assembly’s very rigid standard,” Rabbi Simon said. “I think the reality is that we’re divided.”