Useful ideas from David Bernstein, who makes an interesting point about the importance of J Street:
[A]s a perusal of the comments on any major liberal blog will show, and as public opinion polls also show, Israel is quickly losing support on the American liberal-left. It's vitally important that pro-Israel "progressives" have a home in which they can advocate both for Israel within the left, and for peacenik policies within the general American political and pro-Israel contexts.
That said, he has thoughts, among them this one:
During the Cold War, there were anti-Communists, and what one wag deemed "anti-anti-Communists." The anti-anti-Communists were people who purported to be against Communism, but they spent almost all their efforts denouncing the "right-wing" anti-Communists, and precious little fighting Communism. Similarly, JStreet risks claiming to be "pro-Israel," but really in practice being primarily a lobby against pro-Israel people who are further to the right, and spending precious little time battling truly anti-Israel folks on the Left. (Would that make JStreet anti-anti-anti-Israel? Or just "anti-pro-Israel"?) Most of its energy so far, from what I can tell, has been spent attacking "right-wing" Jewish groups and individuals, and even Israeli government policies, and precious little battling the extreme hostility to Israel one often finds on the progressive left.