When J Street, the “pro-Israel, pro-peace process” group that has become a lightning rod for volcanic differences in American Jewish life, distributed the schedule for its upcoming national conference, nervous members of Congress were quick to note one session: a panel on the boycotts, sanctions and divestment movement that will include a leading Jewish supporter of BDS.

That, in a nutshell, points to what could be the biggest problem facing the political action committee and lobby as it nears its third anniversary.

“They want to be all things to all people on the left — and that’s an extraordinarily wide range of people,” said Gilbert Kahn, a Kean University political scientist. “That means reaching out to groups that are going to make members of Congress very nervous.”

J Street has consistently rejected BDS as a strategy for advancing the peace process. But it has had to tread cautiously in an environment in which many supporters believe selective economic sanctions can ultimately benefit a Jewish state that needs to come to terms with its neighbors, activists close to the group say.

And that makes the other group critical to J Street’s success — members of Congress who support Israel but dislike some of its policies — wary of too close an embrace.

“J Street’s leaders feel that they have to give something to those further to the left in our community, and that is creating some friction with members of Congress who should be their friends but who are very nervous about some of its supporters,” said a congressional staffer who has worked with J Street since its creation in 2008.

While mistakes and confused communications have boosted J Street’s legion of angry opponents, the group’s fundraising remains strong and its grassroots continue to grow. Next week’s conference in Washington will feature some political and administration heavy hitters, including Dennis Ross, President Obama’s senior adviser on Middle East issues, but also some striking omissions, including representatives of the Israeli Embassy, which declined to provide any speakers.

J Street leaders say a mid-course correction is in progress that, while unlikely to dampen the hostility of critics, may ease the concerns of the group J Street needs the most: centrist, pro-Israel members of Congress who are still critical of current Israeli policies.

“At times we haven’t paid sufficient attention to the music,” said J Street’s founder and president, Jeremy Ben-Ami. “Our lyrics are correct, our policies and positions are in line with majority views in our community, but we’ve come on slightly too edgy, too ready to hit away at people we don’t agree with. That rough edge hasn’t been helpful.”

Detractors say a string of recent embarrassments — including the group’s less-than-truthful account of billionaire financier George Soros’ role in its funding, the recent defection of pro-Israel Rep. Gary Ackerman (D-L.I./Queens) and Birthright Israel’s cancellation this month of a joint trip with J Street’s campus affiliate — have set the group on course toward irrelevancy.

Kenneth Wald, a University of Florida political scientist and director of the school’s Center for Jewish Studies, said that despite the mistakes and the concerted opposition, the jury is still out on J Street’s future.

“Overall, my sense is that they’ve been successful in giving voice to people who previously felt they didn’t have one on these issues,” he told The Jewish Week. “They’ve introduced a new tone to the discussion. But you haven’t seen much change in Congress or in the administration. The Obama administration hasn’t taken positions it wouldn’t have taken without J Street.”

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J Street’s birth announcement in 2008 ignited an outpouring of opposition that has only intensified as the group scrambled for a toehold in the turbulent world of Jewish politics. Much of that reaction was the inevitable result of the fact J Street was created to challenge the preeminence of the mainstream pro-Israel lobby in Congress.

“The Jewish community has always been strongest on Capitol Hill,” said David Bernstein, executive director of The David Project. “Opposition to J Street was so strong at first because J Street was operating on the Capitol Hill stage, which potentially could weaken the established pro-Israel community’s strength there at a critical time.”

And J Street “did a much more effective job of rolling out their brand” than the pro-peace process groups that appeared on the scene in the 1980s and 1990s, and which were largely ignored by the Jewish establishment.

Other analysts say J Street threatened that establishment because of its melding of Capitol Hill lobbying with campaign finance — the formula that propelled AIPAC, backed by a vast network of pro-Israel givers, to its status as one of Washington’s pre-eminent lobbies.

And some of the anti-J Street furor is a function of the increasingly loud and effective right-wing faction in the community that portrays all dissent as treachery.

“My experience with J Street is that the people who didn’t like them coming in, like them even less now, and that the people who were sympathetic with their agenda are still sympathetic, even if they have lost patience with some of the things J Street has done,” said Rabbi Jack Moline, the Conservative movement’s longtime political action point person.

But “there also has been as devoted a campaign against J Street as I have ever seen by the element in our community that has campaigned in the same way against President Obama,” he added. “There is an element that is working very hard to discredit anybody who disagrees with them. They are louder and more organized than the voices on the left.”

When J Street opened its doors almost three years ago, some Jewish leaders also feared the left-of-center group would likely have the ear of a new Democratic administration.

“What scared people during their first year is that they seemed to have an interface with the new Obama administration,” said Jacques Berlinerblau, a professor of government at Georgetown University and director of the school’s Program for Jewish Civilization. “They were seen as cocked and loaded, in terms of having a receptive audience for their policy positions at the White House and State Department.”

But what he called the “hysterical” reaction to J Street had deeper roots, Berlinerblau argued.

Critics frequently charge the group with being a haven for intermarried, Reform and secular Jews, suggesting that at least some of the fierce opposition is just another front in the ongoing “who is a Jew” wars, Berlinerblau said.

“There is a perception that even if J Street has never associated itself with secular Judaism, it’s a place where the secular voice can feel comfortable,” he said. “That enrages many, and makes the reaction against J Street particularly strong.”

Rabbi Sidney Schwarz, a senior fellow at CLAL: The National Jewish Center for Learning, put a somewhat different spin on the same idea.

Among Israel’s most ardent defenders in this country “there’s no question we’re seeing an effort to narrow the definition of what it means to be pro-Israel,” he said.

The attacks on J Street reflect "a generational shift away from instinctive Jewish tribal loyalties" said Rabbi Schwarz, who wrote a book on the subject, “Judaism and Justice: The Jewish Passion to Repair the World.”

“Every institution that was once fundamental to the community is at risk,” he continued, “because the generation that is moving up the ranks doesn’t have the same level of commitment to join and participate.”

J Street, Rabbi Schwartz said, is “seen as a giant magnet for those who do not have those tribal loyalties.”

Rabbi Joshua Hammerman, spiritual leader of Temple Beth El in Stamford, experienced some of the furor surrounding J Street first-hand when his synagogue sponsored a debate featuring founder and president Jeremy Ben-Ami and Harvard lawyer Alan Dershowitz, a strong critic of J Street who disputes its claim to being “pro-Israel.”

J Street’s creation was a “direct shot across the bow of the Jewish establishment,” the rabbi said. “It goes way beyond the question of Israel and West Bank settlements.”

Rabbi Hammerman disputed the argument of some critics that new perils facing Israel demand a united front by American Jews. “It’s scary; there’s no reason for this to be happening now,” he said. “This isn’t 1967 or 1973.”

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Even some critics agree that the campaign against J Street sometimes goes over the top. But there’s little doubt J Street has also been hobbled by some major blunders and an aggressive lobbying style that has generated friction with some lawmakers who gravitate toward the J Street orbit.

Its criticism of Israel’s policies in the 2008-2009 Gaza war triggered a fierce reaction from even pro-peace process leaders like the Union for Reform Judaism’s Rabbi Eric Yoffie.

J Street’s persistent denial that it was getting funding from George Soros was revealed to be a lie last year, a big PR victory for bailiwick anti-J Street activists who have argued the group was just another political arm of the controversial financier.

“The issue wasn’t Soros himself — he really isn’t much of an issue with most American Jews — but the members of the press and the community who felt they were lied to,” said Brandeis historian Jonathan Sarna.

While Soros is not radioactive to most congressional Democrats — many of whom benefit from groups he supports — the way the issue was handled by J Street added to congressional skepticism about the group’s competence; Sarna said it resulted in “lost credibility” with the press.

Potentially just as damaging was the recent appeal by J Street to the administration to avoid vetoing a proposed UN resolution condemning Israeli settlement activity, a resolution it said was consistent with longstanding U.S. policy. Even some lawmakers who sympathize with J Street’s positions cringed at the idea of using a UN resolution to push Israel.

Rabbi Hammerman said that “appearing to endorse using the United Nations as a lever was about the dumbest mistake anybody could make.” It was a mistake that may have cost J Street its most important congressional backer, Ackerman, who wrote that after seeing J Street’s position on the UN vote, “I’ve come to the conclusion that J Street is not an organization with which I wish to be associated.”

The group took additional hits for its angry response to Ackerman’s statement, for which it later apologized.

For his part, J Street’s Ben-Ami conceded the group has made mistakes and promises changes. “I have no doubt our appeal continues to grow, but we need to be more nuanced; we need to be moderate in what we ask of members of Congress. After two and a half years, we’re finding the right tonality. We’re not perfect, but the curve is in the right direction.”

Brandeis historian Sarna says maybe — but a lot depends on finding ways to satisfy both of its natural constituencies without scaring off either.

“Like any opposition group, J Street encompasses a broad spectrum, from people like Jeremy — whose commitment to Israel cannot be doubted — to people who are much more dubious,” Sarna said. “They seem torn between their desire to build a broad tent and their efforts on Capitol Hill. That is the tension under which they operate.”