There's a discussion between Nick Cohen and Anthony Julius here about anti-Semitism and the left. It's introduced by Daniel Johnson who says:
In this country today, and indeed across the West, anti-Semitism is no longer the preserve of the extreme Right. It has become embedded even in the respectable salons and newspaper offices of the Left.
Quite so. Amongst much else of interest there's this point from Anthony:
Having my own criticisms of Israel shouldn't be a precondition for taking a position on the anti-Semitism of some views of Israel. Because it feels to me that it's entirely possible to say this or that is anti-Semitic while, so to speak, keeping one's own counsel about one's own views on it.
.....
I think that Netanyahu has been a disaster for Israel. I think the settlement policy is a disaster for the future of that bit of the Middle East. I don't really feel I need to say that in order to then go on to say, I think that a very significant amount of what passes for anti-Zionism is a rewriting of received anti-Semitic language in ostensibly anti-Zionist terms. It feels to me that one can say the one, one can say the other - what's important is that it should be possible for Jews and others to say, without that kind of precondition, "This is wrong, stop it" - without, so to speak, having to produce their own credentials.
It should go without saying. You don't have to 'qualify', so to say, to name anti-Semitism when you see or hear it; neither as a Jew nor as anyone do you have to. Just as criticism of Israel isn't necessarily anti-Semitic, neither is some specific stance towards Israel required before one can have a view about racist attitudes towards, or representations of, Jews.