The recent diplomatic row between Saudi Arabia and Iran over the Saudi government’s execution of a Shia cleric both exemplifies and deepens the division between Shias and Sunnis within Islam. Saudi Arabia and Iran are respectively the Sunni and Shia superpowers within Islam and they are in a Cold War. Longtime observer of Islam Robin Wright details the conflict in a piece worth reading in The New Yorker.
These sentences from the final paragraph are stark:
The current split mirrors a fundamental ideological and strategic division across the Middle East that is now at least as significant as the Arab-Israeli divide, which defined Mideast conflicts over the past six decades. The escalating sectarian rift in recent years is also one of the deepest fractures since the original schism between Sunnis and Shiites, nearly fourteen centuries ago, shortly after the death of the Prophet Muhammad.