Finally, a leader has spoken about the real, essential differences in the struggle between the West and Islam, as it emanates from a contest within Islam itself over the most important things. With startling—indeed alarming—clarity, Pope Benedict XVI told his audience in Regensburg, Germany, that not only is violence in spreading faith unreasonable and therefore against God, but that a conception of God without reason, or above reason, leads to that very violence. To ensure everyone knew what he was talking about, the pope quoted from a 14th-century Byzantine emperor, Manuel II Paleologus, who was besieged by Islamic forces attempting...