WASHINGTON (JTA) – Rep. Brad Sherman withdrew from a forum for skeptics of President Barack Obama’s Iran nuclear strategy, saying an ad for the event was “vulgar.” Sherman has been one of the sharpest critics in his party of the Obama administration’s role in the nuclear talks between Iran and the major powers. “I cannot appear at a forum which was advertised using an unwarranted incendiary personal attack,” Sherman (D-Calif.) said Monday in a statement released just an hour or so before the event at a Senate office building on Capitol Hill.

Rabbi Shmuley Boteach, the event organizer, in a full-page advertisement accused National Security Adviser Susan Rice of turning a blind eye to genocide and juxtaposed a photo of her face next to skulls. Boteach criticized Rice for her own criticism of Israeli Prime Minister Benjamin Netanyahu’s speech before Congress on Tuesday, March 3. Rice said the perception of partisanship was “destructive” of the U.S.-Israel relationship. The ad referred to Rice’s opposition when she was a staffer for the Clinton administration National Security Council to using the word “genocide” when describing the mass killings in Rwanda at that time. She has since apologized for that position.

An array of Jewish groups strongly condemned the ad.

“Nothing has done as much to unify the Jewish community, and nothing has done so much to bring the Jewish community in agreement with the Obama administration, as this ad,” Sherman said.

Elie Wiesel, the Holocaust memoirist, also was scheduled to appear at the event and did not cancel.