The violence by Muslims responding to comments by the pope fit a pattern that has been building and accelerating since 1989. Six times since then Westerners have done or said something that has triggered death threats and violence in the Muslim world. Looking at them in the aggregate offers useful insights. 1989 - Salman Rushdie's novel The Satanic Verses prompted Ayatollah Khomeini to issue a death edict against him and his publishers, on the grounds that the book "is against Islam, the Prophet and the Koran." Subsequent rioting led to more than 20 deaths, mostly in India. 1997 - The...