Political Islam returned to the world stage with Ruhollah Khomeini's 1979 revolution in Iran, which became the most aggressive patron of Muslim radicals outside its borders, including Hamas in the Palestinian territories and Hezbollah in Lebanon. Until very recently, an oil-price windfall gave the Iranian state ample resources to pursue its agenda at home and abroad. How, then, should we explain an eruption of social pathologies in Iran such as drug addiction and prostitution, on a scale much worse than anything observed in the West? Contrary to conventional wisdom, it appears that Islamic theocracy promotes rather than represses social decay....