Look behind the curtain of virtually every major problem in the Middle East, and you will find Iran: killings in Iraq; arms and money for Hezbollah's assaults on Israel and Hezbollah's attempts to usurp the elected government of Lebanon; support of Syria as the hotelier of the region's major terrorist groups; support and training of Hamas, Palestinian Islamic Jihad, and sleeper networks in countries beyond; promotion of a messianic revolutionary ideology that has deepened the Sunni-Shiite divide; the reckless seizure of 15 British sailors and marines as hostages; and defiance of the U.N. in pursuit of nuclear weapons. Only the...