My initial response was that Netanyahu was chicken. I think that is the probable cause of his fear of attending the conference. It is clear that this 'Summit' is intended to promote Sanctions against Iran while promoting the US/Russian concept that reductions of nuclear weapons are in order. Netanyahu is clearly too cowardly to confront Obama again. Netanyahu is afraid. He has good reason to be afraid. He has convinced the world that Israel is absolutely opposed to regional peace. His presence outside Israel something he is too cowardly to indulge. Bwaaak! Cluck, cluck.
Iran: IAEA visit to U.S. Senate damages UN neutrality (DPA)