One of the most significant outcomes of the Arab uprisings is the existential threat Shia and Sunni feel from one another. Over the years, Sunni fighters in northern Lebanon told me they went to fight in Syria to battle the “Shia threat.” Sunnis in Bahrain believe the Shia want to overthrow their Sunni government, and the leading Salafis in Saudi Arabia believe they need to run a campaign to discourage Sunnis across the region from engaging with the Shia.

Their religious difference, once overlooked or understated, is now one of the most prominent features of Arab identity. Even in a country such as Egypt, an outlier to the central conflicts being waged in Syria, Iraq and Yemen, the Shia-Sunni divide is growing and affecting domestic and regional relations. Acknowledging the depth and power of sectarian sentiment in today’s Middle East is central to our understanding of this vital, and volatile, region.

Geneive Abdo, author of The New Sectarianism: The Arab Uprisings and the Rebirth of the Shi’a-Sunni Divide, is a senior fellow at the Rafik Hariri Center for the Middle East at the Atlantic Council in Washington, DC. Her trip to Egypt was funded by a grant from the Pulitzer Center.

Image: Al Azhar Mosque in Cairo, Egypt. Wikimedia Commons/Creative Commons/Diego Delso