Iraq: One Nation Under Allah :: Business Week

Robert J. Barro writes:

In 2000, among the 40 countries where more than 50% of the people were Muslim, 28 (or 70%) had a state religion. In contrast, among the 91 countries with more than 50% in a single non-Muslim religion, 42 (or only 46%) had a state religion. We found that half of the Muslim/non-Muslim difference arose because the share of population that adhered to the most popular religion was higher in Muslim countries. The rest of the difference involves a greater tendency by government to curb religious freedoms in Muslim countries. . . . our results suggest that overall Muslim share, not size of the most popular sect, is what influences the creation of state religion.

Barro lumps Protestants together. But you won't find any country where Protestantism is the state religion - that would be like saying the National Basketball Association is the national team. Instead, as with the Anglican Church in Britain, you will find a particular brand of Protestantism is the state religion. (In Britain, Anglicanism isn't even the largest Protestant denomination.) Looked at from this perspective, some of the 91 countries with more than 50% in a single non-Muslim religion are majority Protestant but have no majority denomination, and are unlikely (Britain being an exception) to have a state religion. Islam may therefore be more similar to other religions in this respect than Barro's numbers suggest.