Fouad Ajami analyses the struggle for influence along the Fertile Crescent—the stretch of land that runs from Iran’s border with Iraq to the Mediterranean—among three of the regional powers that have stepped into the vacuum left by the West: Iran, Turkey, and Saudi Arabia.

He explains that, of the three powers competing for influence, Saudi Arabia and Iran are in it for the long haul. Each of those powers has a sense of mission and constituencies that enable it to stick it out and pay the price for a sphere of influence. Ajami details each country’s prospects for supremacy and asserts that Iran must ultimately be reckoned to be the strongest.