Jerusalem will soon have to confirm its final Road Map decisions on "peace." Then, Prime Minister Binyamin Netanyahu will need to determine whether the still-fractionated Palestinian side is willing and able to overcome some of its deepest cultural roots. Without such a determination, any formal agreement could be perilous.Here, insight requires memory. Before a resurgent medievalism took hold in the Islamic Middle East, the fraternity of Palestinian terrorist groups had contained many disparate bedfellows. Virtually every Arab enemy of Israel was more-or-less welcome to join in a battle for "national self- determination" against the "Zionists." Today, the fight has changed from a preeminently secular and tactical one, to a struggle that draws heavily upon still-underlying commitments to religious sacrifice.In ancient Greece, Plutarch's Sayings of Spartan Mothers identified the exemplary female parent as one who had reared her sons for civic sacrifice. Such a Greek mother was always relieved to learn that a son had died "in a manner worthy of his self, his country and his ancestors." There are lessons here for Israel. The deepest roots of jihadist terror originate from current cultures that embrace similar views of sacrifice. In these mostly Arab cultures, the key purpose of sacrifice extends beyond any presumed expectations of civic necessity. This rationale goes to the very heart of individual fear, to the palpable human dread of death.