The big top went up in Jerusalem this week. You could smell the sawdust of committee rooms, see the bunting of acronyms, hear the barkers call delegates to their rows. Then the spotlight swung to the center ring and a placard appeared: “Head of Diaspora and Public Diplomacy.” Drumroll. Cymbals. A familiar surname. And just like that, we had an act.The news, unvarnished: Yair Netanyahu, the prime minister's son, has been advanced for the World Zionist Organization's executive and is slated to