Sarah Palin’s use of the term “blood libel” has provoked a firestorm of controversy within both the Jewish and political communities. For the most part the Left has excoriated Palin for being insensitive to Jewish suffering, while the Right has either defended her use of that historical term or has given her a pass on it. As I mentioned in my last article, I am one of the few liberal Democrats who, while criticizing her use of crosshairs in indentifying contested congressional seats, found nothing objectionable in her her use of “blood libel” as a metaphor to describe what she regarded as a false accusation of complicity in the bloodletting in Tucson.RELATED: How we love to hate (Premium)Can Israel's democracy be saved? (Premium)When learning is no longer important (Premium) Guillotine Politics (Premium)Is Sarah Palin the victim of a blood libel?(Premium)The irony, of course, is that many of the same people on the Left who criticized Palin for insensitivity towards Jewish suffering, have themselves contributed to Jewish suffering by unfairly demonizing the Jewish state and trivializing the increase in global anti-Semitism. They have also given a pass to those on the hard left who have used Holocaust and Nazi references in mischaracterizing Israeli self defense actions. Consider the case of Norman Finkelstein, a hero of the hard left. Finkelstein regularly uses Nazi references in his attacks on Israel. He has said the following about the Israeli Defense Forces: "[I] can't imagine why Israel's apologists would be offended by a comparison with the Gestapo." (This same formulation has been used by Finkelstein’s British clone, Gilad Atzmon and by others on the hard left.) Most recently, Finkelstein, who regularly refers to the Holocaust as a “circus,” responded to a critic with the words “Heil Hitler,” and to Israeli President Shimon Peres’ Christmas greeting to the Christian world with the words, “And a ‘Heil Hitler!’ to you too.” He has also offered the following advice to Israelis, when they travel abroad:“Do not raise your arm at 45 degree angles and shout ‘Heil Hitler!’ Do not sing or hum ‘Israel uber Alles!’”So proud is Finkelstein of his references to Hitler that he regularly includes them on his website. Other Finkelstein misuses of the Holocaust include calling prominent Jews “Nazis” and comparing them to Eichmann, Streicher and Ribbentrop. He has also said they are “parasites” who “resemble stereotypes straight out of Der Sturmer.”Yet, although J Street, which claims to be a pro-Israel lobby, went out of its way to criticize Palin’s remarks, it has not leveled comparable criticism against Finkelstein and other prominent leftists who abuse the language of Jewish suffering. The reason is obvious: Many J Street supporters adore Finkelstein, cheer him at his lectures and echo his demonization of Israel. J Street does not go after Finkelstein for the same reason it refused to go after Richard Goldstone: If it did, it would lose support from many on the hard left, which it is trying to cultivate. (Incidentally, not only did J Street not condemn Goldstone, one of its leading activist and supporters, Letty Pogrebin praised him as being a modern day prophet and supported the mostegregious statements he made in the report.) Why J Street felt it necessary to enter the kerfuffle about the use of “blood libel” may not be obvious to those who actually believe that J Street is a “pro-Israel, pro-peace” lobby that limits its activities to issues surrounding the Israeli Arab conflict. After all, J Street does not claim to be in the business of defending the Jewish people against defamation as does the Anti-Defamation League. Nor is it a protector of Jewish sensitivities like the Simon Wiesenthal Center. But to those of us who understand what J Street really is, its attack on Palin makes perfect sense. J Street is a lobby for the Democratic Party in general and for the Obama Administration in particular. That’s why it doesn’t deviate from the Obama line, doesn’t criticize the Obama Administration, and doesn’t miss an opportunity to dump on Republicans, even those who support Israel. J Street will respond to this charge of a double standard by arguing that Sarah Palin is a prominent public figure, a potential presidential candidate, while Finkelstein and others on the hard left who abuse the language of Jewish suffering are marginal figures. But that misses the mark. Those of us who are liberals have a special obligation to criticize abusers of the Left, just as those who are conservatives have a special obligation to criticize abusers of the Right, such as Patrick Buchanan. It’s too easy for J Street to pile it on when the alleged abuser is a conservative Republican. It’s far more difficult, and costly, for J Street to go after fellow leftists who abuse language, especially those with large followings among its supporters. But that is their responsibility if they are to assume the role of protector of Jewish sensibilities. I doubt it is a role they are willing to assume, except when it serves the interests of their real clients: the Democratic Party, the Obama Administration and the Left. That is why they went after Sarah Palin, even though her remarks had nothing to do with Israel or peace.Any genuine lobby group for Israel and for peace must assure that support for Israel and for peace remains a bipartisan concern. J Street wants to turn it into a partisan wedge issue that divides Democrats and Republicans, liberals and conservatives, young and old. That’s why they focus so much criticism against Republicans who support Israel. Such divisions do not serve the interests of peace or Israeli security. Postscript: After completing this article, I learned that a Democratic Congressman named Steve Cohen compared Republican statements about the Obama health care reform to "the big lie" told by Joseph Goebbels, saying it's "like [a] blood libel. The same kind of thing." Cohen further posited, "The Germans said enough about the Jews and the people believed it and you had the Holocaust." Professor Alan Dershowitz’s latest book is a novel, The Trials of Zion.