I've mentioned Israeli Ambassador Michael Oren's decision to quite conspicuously refuse to attend the J Street conference next week. Not content to simply plead a busy schedule, Oren suggested that J Street might be anti-Israel and thus an inappropriate forum for a visit.

But Tzipi Livni, head of the main opposition party, Kadima, has just sent a letter just as conspicuously disassociating herself and her party from Oren's and (more broadly) the Likud government's position.

That is a decision of great significance.

Quite apart from the policy disputes behind the J Street controversy (and Livni makes clear that she is not necessarily on board with all J Street's positions), the Netanyahu government's stance in this case represents a quite novel and very shortsighted decision to, in essence, write off a big chunk of American Jewry and class them amongst Israel's foes. To be fair, much of the dispute here is about how much of American Jewry J Street represents. My hunch is that Oren/Netanyahu are both trying to answer the question by force, as it were -- rhetorical force, but force nonetheless -- but also genuinely misreading where the American Jewish community is on the big issues in the Middle East. Now Livni has made J Street a point of division within Israeli politics as well.