Few Jewish organizations have generated feelings — pro or con — as intense as those ignited by J Street, the pro-peace process lobby and political action committee created two years ago to provide a left-of-center address for politicians and activists who support more aggressive U.S. peace process diplomacy.

That intensity took another quantum jump with last week’s Washington Times disclosure that the group has been getting substantial donations from financier George Soros despite repeated denials from its leaders.

The fact that the lobby lied about receiving support from Soros speaks in part to the critical perception of him in the mainstream Jewish community. A Hungarian-born Jew who escaped the Holocaust as a child, the billionaire has contributed large sums for democratic rights in Central and Eastern Europe. But he has given little if any money to Israel or Jewish causes and has stirred controversy with critical remarks, like blaming Jews for anti-Semitism. Just last week he pledged $100 million to Human Rights Watch, whose bias against Israel is pronounced and longstanding.

But in a sense, Soros is almost beside the point. J Street committed a cardinal sin in Washington by misleading politicians who trusted its integrity. Its leaders acted without regard for the members of Congress they were ostensibly supporting, and sowed a climate of mistrust that can only lend credibility to other claims of its critics, both legitimate and outrageous.

While we strongly disagree with J Street’s continuing emphasis on demands for Israeli concessions while largely ignoring a long list of unmet Palestinian obligations, we also disagree with those in our community who claim it is anti-Israel. Clearly, it recognizes the legitimate rights of Jews to have their own state, and reflects the views of a significant proportion of our community who see negotiations for a two-state solution as an urgent necessity. At times J Street’s opposition to boycotts of Israel and divestment from Israeli companies has held sway among those on the left.

That said, J Street has an obligation to its members and to its primary constituents — the members of Congress and other political figures who agree with its positions — to be truthful and smart when it comes to its brand of activism. The current controversy suggests it has been neither.

The fact that J Street’s donor list was released through an apparent Internal Revenue Service error points to another dimension of the controversy. J Street isn’t alone in trying to keep its donor lists secret. Our community and our nation would be better served by more transparency on the issue of who is paying for the advocacy groups that play such a huge role in the emotional, high-stakes debate over U.S. Middle East policy.