Even though they have a common enemy in ISIS, cultural and religious animosity between Iraqi Sunnis and Iran-backed Shiites may threaten Iraq's fragile military coalition — and derail the American war plan, NBC News reported. The animosities between the two major Muslim sects stem from centuries of bloodshed, as well as a brutal eight-year Sunni-Shiite war in the 1980s. "I will not fight with the Hashad," one Sunni tribal fighter told NBC News, using the Arabic name for Iran's Shiite militias. "They … take their orders from Iran. It's a shame on me if I fight next to an Iranian."
