Sunni-Shia Split Fuels Tensions in Iran War

Centuries-old religious divide between Islamic sects shapes recent military actions in the Middle East

Published on Mar. 4, 2026

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The recent military actions in the Middle East, including Iran's attacks on neighboring countries, are being shaped by the 1,400-year-old religious divide between Sunni and Shia Islam. While the conflict is often framed as the U.S. and Israel against Iran, the underlying tensions between the two dominant Islamic sects are a key driver of the violence and instability in the region.

Why it matters

The Sunni-Shia split is a deeper, more persistent source of conflict in the Middle East than factors like settler-colonialism, U.S. imperialism, or oil. Understanding this religious divide is crucial to comprehending the complex geopolitical dynamics at play in the current Iran war and tensions in the region.

The details

Iran, a Shia-majority country, has attacked several Sunni-led nations in the region, including Qatar, the UAE, Saudi Arabia, and Oman, in addition to targeting U.S. and Israeli interests. This is driven by the longstanding resentment and hostility between Shiites, who see Sunnis as "heretics," and Sunnis, who view Shiites as inferior. The split dates back to a dispute over leadership of the Muslim faith after the death of Prophet Muhammad in 632 CE.

  • The recent military actions in the Middle East have occurred since October 2023.

The players

Sunni Islam

The dominant branch of Islam, followed by the majority of Muslims worldwide and the religion of most regional royalty in the Middle East.

Shia Islam

The second-largest branch of Islam, followed by the ruling clerics in Iran and the Lebanese proxy group Hezbollah.

Zohran Mamdani

The mayor of New York City, a Shiite Muslim who criticized the U.S. and Israeli actions against Iran as "catastrophic" and an "illegal war of aggression."

Amir Avivi

Brigadier General (Reserve) and founder/chairman of Israel's Defense and Security Forum, who said the Iranian regime was "acting in an hysterical way" in its attacks on neighboring countries.

Harold Rhode

A former Pentagon official with expertise in Arab and Muslim religion and culture, who explained the Sunni-Shia dynamics driving the regional tensions.

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What they’re saying

“Shiites call the Sunnis dogs. They don't see them as real Muslims, they see them as heretics.”

— Harold Rhode, Former Pentagon official (Washington Free Beacon)

“They'd kill me before they kill you.”

— Unnamed Sunni Muslim barber (Author's personal conversation)

The takeaway

The Sunni-Shia religious divide is a fundamental driver of conflict and instability in the Middle East, shaping the current Iran war in ways that go beyond the typical geopolitical narratives. Understanding this deep-rooted schism is crucial for policymakers and observers to navigate the complex dynamics in the region.