Will Islam embrace pluralism?

There is, it's often said, no separation of church and state in Islam. And, historically speaking, this is more or less true.

There was no clear separation of church and state anywhere in the ancient world. High priest and ruler were closely identified (and sometimes identical) in ancient Israel and Judah.

Pre-Islamic Iran was officially Zoroastrian. Augustus was not only the emperor of Rome but "pontifex maximus" or high priest — a title later inherited by the popes. The Council of Nicea, which hammered out the Nicene Creed, was convened by the Emperor Constantine. Virtually all Chinese emperors until the fall of the Qing Dynasty in 1912 were called the "Son of Heaven," claiming to rule under "the mandate of Heaven." The doctrine of "the divine right of kings" survived in Europe until the early modern period.

In mediaeval Christendom, rulers routinely demanded veto power over the appointment of bishops and even the right to choose bishops directly. Kings and other secular authorities, in fact, continued to exercise such rights as late as the second half of the 19th century.

Many countries — by no means limited to Muslim ones — have official state churches or state religions. The British monarch, currently Elizabeth II, bears the constitutional title of Supreme Governor of the Church of England, and nominations for bishops in that church are submitted to the office of the Prime Minister, who vets them on behalf of the ruler. Several of Britain's colonies in the New World also had official churches. Connecticut only disestablished the Congregational Church in 1818; Nova Scotia still recognized the Church of England as its official faith until 1850.

Christianity, though, had one distinct advantage in conceiving the separation of church and state: Constantine's intervention in Christian theology was a novelty (and a bad one). And it wasn't until 380 A.D. that Theodosius I, following universal ancient practice — if not the teachings of Christ — officially adopted Trinitarian Christianity as the imperial religion.

Jesus, however, had held no political office, and, in fact, his followers had spent several centuries struggling against often fierce state persecution. Augustine, a leading Christian theologian, laid the foundation for the separation of church and state when writing his "City of God," describing the church as transcending any state.