Congregation B’nai Jeshurun, a large synagogue on the Upper West Side of Manhattan, is known for its charismatic rabbis, its energetic and highly musical worship, and its liberal stances on social causes.

But on Friday, when its rabbis and lay leaders sent out an e-mail enthusiastically supporting the vote by the United Nations to upgrade Palestine to a nonmember observer state, the statement was more than even some of its famously liberal congregants could stomach.

“The vote at the U.N. yesterday is a great moment for us as citizens of the world,” said the e-mail, which was sent to all congregants. “This is an opportunity to celebrate the process that allows a nation to come forward and ask for recognition.”

The statement, at a time when the United Nations’ vote was opposed by the governments of the United States and Israel, as well as by the leadership of many American Jewish organizations, reflected a divide among American Jews and a willingness to publicly disagree with Israel.

Clergy at several Jewish congregations have, in various ways, spoken out sympathetically about the United Nations’ vote. But B’nai Jeshurun stood out because of its size and prominence, and reaction from congregants was swift. Allan Ripp, a member, said he and his wife were appalled.

“We are just sort of in a state of shock,” he said. “It’s not as if we don’t support a two-state solution, but to say with such a warm embrace — it is like a high-five to the P.L.O., and that has left us numb.”

Other congregants, however, said it was a bold move that they welcomed.

“I thought it was very courageous of them,” said Gil Kulick, a congregant. “I think as of late there has been a reluctance to speak out on this issue,” he added, “and that’s why I was really delighted that they chose to take a strong unequivocal stand.”

American Jews have long had a vigorous, and sometimes vitriolic, debate about the positions of the Israeli government and the peace process with the Palestinians. But the tendency has been to keep critical views within the fold.

“At most times we impose a kind of discipline upon ourselves — nobody imposes it on us — particularly on a matter that the Israeli government has asked for unanimous support from the Jewish community,” said Samuel Norich, the publisher of The Forward, a Jewish affairs weekly based in New York. “When they speak out, that is rare,” Mr. Norich said of mainstream congregations.

Gary Rosenblatt, the editor and publisher of The Jewish Week, the largest-circulation Jewish newspaper in the country, said, “I think the sense of a need for a unified front in the American Jewish community is breaking down.”

In White Plains, a group of synagogues from different branches of Judaism — Conservative, Reform and Reconstructionist — sent an e-mail to congregants after the United Nations’ vote expressing cautious optimism about Palestine’s new status.

“For their own reasons, most of the American Jewish organizations felt it was necessary to fall into line,” said Lester Bronstein, a rabbi at Bet Am Shalom Synagogue in White Plains and one of the signers of the letter. “I think what we said is indicative of what more and more rabbis believe, and more and more, but in trickles, are able to say it.”

 The rabbis at B’nai Jeshurun — J. Rolando Matalon, Marcelo R. Bronstein and Felicia L. Sol — did not respond to requests for comment on the e-mail, which was also signed by the president of the synagogue’s board of directors and its executive director.

While its gist — that the vote could be a step toward a two-state solution and Middle East peace — was not surprising to congregants, its tone and its timing were jarring, some said.

“It’s very shocking to many of the congregants that this position was taken publicly and this e-mail was sent around,” said Eve Birnbaum, a member of the congregation for about 15 years.

“I am very dismayed, as a longstanding member of the synagogue, that the rabbis and the board would take a position that is contrary to what many members believe, contrary to the peace process,” she added.

It was not immediately clear how widespread opposition to the rabbis’ e-mail has been within the congregation, but Mr. Ripp said he had been inundated with messages from people upset about the rabbis’ statement, and some members had posted comments online and circulated e-mails expressing concern.

But others supported the action.

“The statement reflected the views of the rabbinate and the leadership,” said Scott A. Weiner, 63, a congregant. Mr. Weiner said that during the Gaza conflict, he had been among about 20 people in Israel with Rabbi Matalon, the congregation’s senior rabbi, and that the group had been forced into bomb shelters several times.

“There is an unwavering commitment of support for the State of Israel,” he said. “But just as Israeli society is multidimensional, so, too, is the congregation.”

B’nai Jeshurun, which is not affiliated with any of the major branches of Judaism, generally worships in an elaborate Moorish-style sanctuary on West 88th Street; its best-attended services, which draw several thousand people, spill over into a church nearby.

Among those attending have been Representative Jerrold L. Nadler, a Manhattan Democrat;  the actress Debra Winger; the actor Rick Moranis; and Attorney General Eric T. Schneiderman.

The synagogue has attracted attention for its success at energizing a once-struggling congregation. During services, congregants are encouraged to express themselves and often clap and even dance to the music, which is at times accompanied by keyboard, congas, mandolin, flute, guitar or cello.

Lectures and events are popular not only among members, but also among young single Jews seeking social connections.

A heated debate also ensued online over an e-mail that Rabbi Sharon Brous of Los Angeles sent to her congregants during the Gaza conflict that said the Palestinian people “are also children of God, whose suffering is real and undeniable.”

Her sentiment was attacked by Rabbi Daniel Gordis,  senior vice president at the Shalem Center in Jerusalem, in a column for The Times of Israel.

“I wanted her to tell her community to love my family and my neighbors more than they love the people who elected Hamas and who celebrate each time a suicide bomber kills Jews,” he wrote. “Is that really too much to ask?”

Rabbi David Ingber of Romemu, another liberal synagogue on the Upper West Side, said the criticism of Rabbi Brous had helped inspire him to lead his congregants in a prayer for the children of Gaza, as well as for the Israeli people.

Still, he said, he would not go as far as sending an e-mail like the one from B’nai Jeshurun because he feared it would be divisive.

“This is the constant question among liberal, progressive Jews: what does it mean to support Israel?” he said. “Does it mean never criticizing Israel?”