WASHINGTON -- Istanbul sits astride the Bosphorus, a sophisticated, tolerant place that seamlessly mixes Occident and Orient. Now it has been stricken by the cancer of terrorism.

The attack on two Turkish synagogues is not just an instance of terrorism. It is the deliberate targeting of civilians that reflects the virulent anti-Semitism that has despoiled our world for centuries.

It is hard for people steeped in the humane, liberal values that we want to believe everyone shares to understand the massacre of innocents. But terrorism is surprisingly common. Although Americans were taken unawares on 9/11, many other peoples have long suffered from the murderous attention of terrorists.