In 1942, Haj Amin el-Husseini, then "prime minister" of a pan-Arab government formed in Nazi Berlin, broadcast from Germany to his numerous disciples in the Arab world: "Slaughter the Jews wherever you find them. Their spilled blood pleases Allah." This virulent message has clearly been revived in Arab, particularly Palestinian, society, as it was when still-revered Husseini was its all-powerful warlord. Sajid Abu Alous, the 18-year-old ringleader of a gang that recently roamed the streets of Jerusalem in order to gun down Jewish passersby, echoed the Nazi-collaborator's sentiments to the full, when he remorselessly declared a few days ago that...