Saudi Arabia dominates the culture of mainstream, majority, Sunni Islam - and has been an American military ally since WWII. Iran dominates the world of Shiite Islam and has been openly hostile to the West, and to pro-Western Arab nations, for almost 40 years. The open hostility between the two regional rivals takes many forms, including a proxy war in Yemen, just to Saudi Arabia's south, and in Iraq, and in Syria, and several other battlegrounds. If this progresses to war, leadership of the Islamic world is ripe for the taking, and this could escalate to