Bernie Madoff deceived his closest friends by committing what the sociologists call an "affinity crime." It turns out that it's easier to trick people you're close to: Nobody asks his aunt for a grocery receipt. It's simple: You're less likely to practice due diligence when your expressed doubts might be construed as insults, or evidence of bad faith. How to establish and maintain a warm relationship with someone, while at the same time questioning him diligently, will always be a human dilemma. Bernie knew that better than anyone on the planet.

Jewish leaders who want good relations with Muslim groups face a similar dilemma. Cases abound where Muslims -- who had established good communal relations -- turned out to have been masters at deception. Right here in Boston, two ostensibly moderate Muslim leaders fooled everyone. The founder of the Islamic Society of Boston (ISB) rose to great prominence and gained access to Presidents Clinton and Bush. He's now in jail for running money to Al Queda. The ISB's outreach director, schmoozed with Boston rabbis until he was caught cursing Jews in Arabic journals.

Unfortunately, it's not only a Boston phenomenon. FBI investigations nationwide found concrete evidence that many of the Islamist organizations most active in interfaith dialogue groups around the country had at the same time worked to promote their radical politico-religious goals - radicalizing America's historically moderate Muslim communities, fundraising for violent Islamist movements abroad, and of course, influencing public opinion against Israel. This FBI evidence also showed that radical Islamists have sought dialogue as a way to mask their true agenda and to incrementally gain legitimacy in mainstream society.

So what are Jewish leaders to do? This is uncharted territory. It's different than dialogue with post-Holocaust Catholics. Many Jews who "dialogue" are clueless about Islamist ideology and simply can't bring themselves to think that anyone who speaks softly and smiles at them might be with a radical organization. Yet there are leaders who are partially or even fully aware of the identity of their "partners," and who believe - or hope -- that by dialoguing with the radicals, they might entice them toward peace and moderation. These people have yet another dilemma: what to tell the Jewish community?

Think about it. How can Jewish leaders openly tell their communities that they are undertaking, without a community vote, to engage with people who may be actual anti-Semites with possible ties to terror, and that they have to do it by not pressing their dialogue partners too hard on these issues, because they honestly believe that by establishing warm relations they may help change the situation for the better? How can they say that they feel the need to reach out -- but at the same time they fear they are being used? The answer? They cannot.

This must be agonizing. There is no transparency, neither with the Muslims nor with the Jewish community. The only solution is to have an open and honest dialogue within the Jewish community about these extraordinarily difficult dilemmas.