A Women's March leader, Tamika Mallory, attended a speech by Louis Farrakhan, notorious for antisemitic bigotry (which manifested itself in the speech). When called out on it, Mallory doubled-down with a remark ("If your leader does not have the same enemies as Jesus, they may not be THE leader!") that was less of a antisemitic dogwhistle than a bullhorn.
For the most part, the response of the other Women's March leaders has been to defiantly have her back (here's a particularly terrible intercession from Linda Sarsour). At the same time, there's been virtually no public justification as to why the rather obvious antisemitism of Farrakhan should be excused. There's been no effort to defend the things he says about Jews, no attempt to argue that his perspective on Jews is in fact in bounds.
This oddity -- defiant refusal to concede any ground on the antisemitism count, coupled with no attempt to actually rationalize the antisemitic content -- demands explanation. My hypothesis is this:
Leftists don't like thinking about antisemitism in their own ranks. At the same time, they'd never admit this is so. Fortunately, most antisemitism controversies that implicate the left relate to Israel in some fashion, and so they can respond with their favorite chestnut: "criticism of Israel isn't antisemitic." On face, this response assures the audience that they do care about antisemitism (the "real" antisemitism), but that the case at hand doesn't count as such (that it never seems to count as such is suspicious in its own right. But leave that aside.).
But Farrakhan's antisemitism isn't really tied to Israel. Which means that the stand-by response won't work. And these leftists are left flummoxed, because they don't really have another thought on antisemitism beyond "criticism of Israel isn't." Forced into a situation where it seems necessary to say something else, they find themselves at a loss. Suddenly, they can't play their get-out-of-talking-about-antisemitism-free card.
And this is revealing. If the problem really was Israel, the Farrakhan case shouldn't present any difficulty. But if the problem is that these leftists just don't want to have to reckon with antisemitism in their community (and Israel is a convenient but ultimately epiphenomenal factor), then Farrakhan presents a huge problem.
We're getting an excellent peek into who falls into which category here.