The same question could be asked about Nazi Germany. Had someone been asked in the 1890s to identify the epicenters of anti-Semitism in Europe, the answers would probably have been Paris (where Alfred Dreyfus, a French military office of Jewish descent, was framed as a spy and unjustly imprisoned) and Vienna (whose bigoted mayor, Karl Lueger, became Hitler’s inspiration and role model). Why was it Germany that conceived and executed the Final Solution, an elaborate program with the sole purpose of exterminating Europe’s Jews?

The answer is the same in both cases: Anti-Semitism becomes deadly only when a culture, nation or faith suffers from a cognitive dissonance so profound that it becomes unbearable. It happens when the way a group sees itself is contradicted by the way it is seen by the world. It is the symptom of an unendurable sense of humiliation.

Christianity, which had been transformed by the conversion of the Roman Emperor Constantine in the fourth century, found itself overtaken by Islam by the 11th century. Germany, which had seen itself as the supreme nation in Europe, was defeated in World War I and then punished under the Treaty of Versailles.

These humiliations resulted not in introspection but in a search for foreign culprits—for external enemies who could be blamed and destroyed. The parallel in Islam over the past century was the defeat and dissolution of its one remaining bastion of imperial power, the Ottoman Empire, in 1922. Six years later, radical political Islam was born in Egypt in the form of the Muslim Brotherhood.