I'll join everyone in linking to Peter Beinart's excellent essay on American Jews and Zionism.
I knew that the American Jewish establishment was in bad shape -- by which I mean, cut off from the reality of American Jewish politics -- when they put Elliott Abrams on the road as a featured speaker at fundraising events. But to find out that they're hiring Frank Luntz to conduct focus groups...well, that's just pathetic (especially since what they get for their trouble is typical Luntz garbage about jettisoning the word "Palestinian" for the word "Arab").
The elephant in the room that Beinart doesn't discuss is that Israeli leaders may feel that they don't need Jewish support in the United States, because they can substitute Christian evangelical support, with the latter less likely (or at least perceived to be less likely) to produce any sorts of constraints on the Israeli government. Personally, I think shifting from a American base of American Jews to a coalition of Orthodox Jews, evangelical Christians, and ideological neo-cons would be a tragic mistake for Israel...but I can certainly understand the appeal for Likud politicians.