Like other Abrahamic faiths, Islam has multiple schisms. The greatest divide is the Sunni-Shia division. Historically, Sunnis elected Abu Bakr, a friend of Mohammed, as the first caliph, or leader of the Islamic community. Shia's elected Ali, Mohammed’s cousin and son-in-law. Since this divide, political and cultural differences have arisen. Some Sunnis do not even consider Shia's Muslim, and vice versa, as this data from Pew Research shows. 85% of the Islamic community identifies as Sunni; 15% are Shia.

If American foreign policy was more aware of these divides before going into Iraq, more strides would have been made. The uprising of ISIS has a lot to do with sectarian violence post-Saddam. We need better anthropologists working for the White House!